JPH1148949A - Vacuum booster - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized vacuum booster. SOLUTION: The input/output ratio of a vacuum booster during its normal operation depends on the ratio of the total area of a first contact part 301 and a second contact part 302 receiving reaction force from a reaction disk 54 to the area of the disk 54 contacting with an output rod 55, while that ratio during the operation of an automatic actuator 48 depends on the ratio of the area of the second contact part 302 receiving reaction force from the disk 54 to the area of the disk 54 contacting with the rod 55.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum booster, and more particularly, to a vacuum booster applied to an automobile.

[0002]

2. Description of the Related Art Conventionally, in a vehicle, a negative pressure booster has been employed as a brake booster for reducing an operation force during braking.

This negative pressure type booster uses a suction negative pressure of an engine or a negative pressure of a vacuum pump as a boosting source, and utilizes a pressure difference between the negative pressure and the atmospheric pressure to depress a brake pedal of a vehicle driver. The above-mentioned force is applied to the brake device via hydraulic pressure, and is the most common system as a brake booster.

[0004] For example, Japanese Patent Application Laid-Open No. 9-2246 discloses that
In addition to the driver's input, in response to driving or brake operation conditions, for example, when the brake pedal operation speed of the vehicle driver exceeds the limit (at the time of sudden braking), the solenoid in the booster is excited. A negative pressure booster equipped with an automatic mechanism for adding and generating an output other than the assisting force by input has been proposed.

The negative pressure type booster disclosed in Japanese Patent Application Laid-Open No. 9-2246 discloses a housing in which a pressure chamber is formed, and is installed in the housing. The pressure chamber is connected to a negative pressure source. A movable wall divided into a constant pressure chamber and a variable pressure chamber selectively communicated with the negative pressure source and the atmosphere; a power piston coupled to the movable wall; and a power piston inside the power piston with respect to the power piston. It has an input member installed to be able to move forward and backward and is movable by a brake operation, and has an annular valve seat for air inflow control facing rearward, and is usually integrated with the input member as the input member moves. A retractable valve seat member, an air outflow control annular valve seat integrated with the power piston and facing rearward, the air inflow control annular valve seat and the air outflow A movable member facing the control annular valve seat and a valve member having a fixed portion hermetically fixed to the power piston and the movable portion being biased forward by a biasing member; In response to the movement of the input member, the variable pressure chamber communicates with the constant pressure chamber and an output reduction action state in which the variable pressure chamber is isolated from the atmosphere, an output holding action state in which the variable pressure chamber is isolated from the constant pressure chamber and the atmosphere, and the variable pressure chamber. A valve mechanism for switching to an output increasing operation state in which the chamber is disconnected from the constant pressure chamber and communicated with the atmosphere, and a first propulsion force of the power piston accompanying movement of the movable wall by the brake operation is output to the outside as a main output. An output member, a solenoid coil and a yoke fixed to the power piston, and moved forward by an electromagnetic attraction force generated by energizing the solenoid coil. A plunger for moving the valve seat member forward with respect to the input member, disengaging the movable portion from the air inflow control annular valve seat, and engaging with the air outflow control annular valve seat. An automatic operation mechanism that applies an auxiliary output to the output member by generating a second propulsive force on the power piston, and is disposed between the input member and the output member;
The input member is moved backward by applying a reaction force corresponding to the first and second propulsion forces generated on the movable wall and the power piston to the input member due to a pressure difference between the constant pressure chamber and the variable pressure chamber. And a reaction force member for constantly moving the valve mechanism from the output increasing operation state to the output holding operation state by moving the valve mechanism to the valve seat member and the input member, and the automatic operation mechanism is operated. Thereby, when the valve seat member is moved forward by a predetermined amount with respect to the input member, the valve seat members abut against each other to restrict the forward movement of the valve seat member with respect to the input member, and the input by the reaction force is performed. An engagement portion that always moves the valve seat member and the input member integrally rearward by moving the member rearward, and an engagement portion disposed in the input member to increase or decrease an input associated with the brake operation. Flip and those comprising an elastic member for increasing or decreasing the predetermined amount by elastic deformation.

[0006] In this conventional vacuum booster, the amount of deformation of the elastic member is increased or decreased by increasing or decreasing the input due to the brake operation, so that the contact portion of the valve seat member and the contact portion of the input member are increased. Is increased or decreased. The movement amount of the valve seat member with respect to the input member is increased / decreased by increasing / decreasing the predetermined amount between the abutting portions. As a result, the ratio of the input of the negative pressure booster to the sum of the main output and the auxiliary output is reduced. Will be changed.

[0007]

However, in the conventional vacuum booster described above, when the predetermined amount between the contact portion between the valve seat member and the input member is increased, the movement of the valve seat member and the plunger is increased. As the volume is increased, the necessity of increasing the size of the automatic operation mechanism including the solenoid, the yoke, and the plunger arises. Further, since the elastic member is provided in the input member, the input member may be increased in size. Increasing the size of the automatic operation mechanism and the input member may eventually lead to an increase in the size of the negative pressure booster itself.

An object of the present invention is to provide a negative pressure type booster that can be downsized.

[0009]

In order to solve the above-mentioned technical problems, a housing having a pressure chamber formed therein, and a pressure chamber disposed inside the housing so as to be able to move forward and backward with respect to the housing, are provided. A movable wall divided into a front chamber communicated with a negative pressure source and a rear chamber selectively communicated with the negative pressure source and the atmosphere, a power piston coupled to the movable wall, and an inside of the power piston. An input member installed to be movable forward and backward with respect to the power piston, and movable by a brake operation; and an input member provided in the power piston, and the rear chamber is moved to the front chamber in accordance with the movement of the input member. And an output holding action state in which the rear chamber is shut off from the front chamber and the atmosphere, and an output increase action in which the rear chamber is shut off from the front chamber and communicates with the atmosphere. A valve mechanism for switching to an operating state, an output member for outputting the first propulsive force of the power piston along with the movement of the movable wall by the brake operation as a main output to the outside of the device, and independent movement of the input member. The valve mechanism into the output increasing action state, generating a second propulsive force on the power piston to add an auxiliary output to the output member, and an automatic operation mechanism between the input member and the output member. And the first power piston
When a thrust is generated, a reaction force corresponding to the first thrust is applied to the input member to move the input member rearward, thereby moving the valve mechanism from the output increasing operation state to the output holding state. The input member is moved rearward by applying a reaction force corresponding to the second propulsion force to the input member when the second propulsion force is generated in the power piston while shifting to the operation state. Then, the valve mechanism is shifted from the output increasing operation state to the output holding operation state, abuts the input member on a rear side thereof, abuts on the output member on a front side thereof, and the reaction force on the input member. A reaction force member that determines a ratio of the sum of the main output and the auxiliary output output by the input member and the output accompanying the brake operation at a ratio of an area where the output member acts and a contact area of the output member; , The automatic actuator A negative pressure booster including a change mechanism that changes the ratio of the area of the input member where the reaction force acts on the input member and the contact area between the reaction member and the output member with the operation of did.

[0010] Preferably, the change mechanism is a negative pressure booster for changing an area of the input member on which the reaction force acts.

More preferably, the input member has a first contact portion that contacts the reaction member at a first area and a second contact portion that contacts the reaction member at a second area. In a normal state, the first contact portion and the second contact portion receive the reaction force from the reaction member, and the changing mechanism causes the input member to react the input member with the automatic operation mechanism. It is preferable that the negative pressure type booster be configured to cause the reaction member to receive the reaction force by contacting the force member with the second contact portion.

More preferably, the first contact portion has an annular shape, and the second contact portion is inserted into a center hole of the first contact portion so as to be slidable in the axial direction of the center hole. Columnar,
The input member has a first restricting portion for restricting a rearward movement of the first contact portion with respect to the second contact portion, and the change mechanism is provided by the reaction member according to the operation of the automatic operation mechanism. It is preferable that the negative pressure type booster be provided with a second regulating portion that regulates the backward movement of the first contact portion with respect to the power piston when the input member moves backward.

More preferably, the valve mechanism is integrated with the input member and is directed rearward to an annular valve seat for controlling air inflow, and is integrated with the power piston and directed rearward. An annular valve seat for air release control,
It has a movable portion facing the air inflow control annular valve seat and the air outflow control annular valve seat, and a fixed portion airtightly fixed to the power piston, and the movable portion is biased by an urging member. A valve member that is biased forward, wherein the automatic operation mechanism is selectively connected to a power source, and sets the valve mechanism to the output increasing operation state by receiving supply of electricity. A solenoid coil and a yoke fixed to the power piston, a plunger moved rearward by an electromagnetic attraction force generated by energizing the solenoid coil, and the power supply on an inner diameter side of the air outlet control annular valve seat. The plunger is disposed so as to be able to move forward and backward, and is moved rearward by the movement of the plunger to move the movable portion to the air inflow control annular valve seat and the air outflow control. Vacuum booster and a valve seat member for spacing the use annular valve seat apparatus is desirable.

[0014] More preferably, the valve mechanism has an annular valve seat for air inflow control facing rearward, and can normally move forward and backward integrally with the input member as the input member moves. A seat member, an air outlet control annular valve seat integrated with the power piston and facing rearward, and a movable portion opposed to the air inflow control annular valve seat and the air outflow control annular valve seat. And a valve member having a fixed portion hermetically fixed to the power piston, and the movable portion being biased forward by a biasing member. A solenoid coil and a yoke fixed to the power piston, the solenoid being selectively connected to a power source and receiving the supply of electricity to bring the valve mechanism into the output increasing operation state; The valve seat member is moved forward with respect to the input member by being moved forward by an electromagnetic attraction force generated by energization of the coil, and the movable portion is detached from the atmospheric inflow control annular valve seat. A plunger engaged with the airflow control annular valve seat, wherein the valve member is always moved rearward integrally with the input member by the rearward movement of the input member due to the reaction force. Force devices are preferred.

More preferably, the valve seat member and the input member abut each other when the automatic operation mechanism is actuated to move the valve seat member forward by a predetermined amount with respect to the input member. It is preferable that the negative pressure type booster be provided with an engagement portion that is in contact with and regulates forward movement of the valve seat member with respect to the input member.

[0016] More preferably, the valve mechanism has an annular valve seat for air inflow control facing rearward, and is normally capable of moving forward and backward integrally with the input member as the input member moves. A seat member, an air outlet control annular valve seat integrated with the power piston and facing rearward, and a movable portion opposed to the air inflow control annular valve seat and the air outflow control annular valve seat. And a fixed portion that is hermetically fixed to the power piston, and further includes a cylindrical valve member whose movable portion is urged forward by an urging member. The input member is selectively connected to an electric power source, and receives the supply of electricity to bring the valve mechanism into the output increasing operation state. The input mechanism is provided so as to be able to move forward and backward with respect to the power piston. The solenoid coil and the yoke, which are integrally moved with the input member with the movement, move the valve seat member forward by being moved forward by an electromagnetic attraction force generated by energizing the solenoid coil, A plunger for detaching the movable portion from the annular valve seat for atmospheric inflow control and engaging with the annular valve seat for atmospheric outflow control, wherein the valve member moves rearward of the input member due to the reaction force. A negative pressure booster that is always moved rearward integrally with the input member is desirable.

More preferably, the valve seat member and the input member are in contact with each other when the automatic operation mechanism is actuated to move the valve seat member forward by a predetermined amount with respect to the input member. It is preferable that the negative pressure type booster be provided with an engagement portion that is in contact with and regulates forward movement of the valve seat member with respect to the input member.

In the negative pressure booster according to the present invention, when the automatic operating mechanism is operated, the area where the reaction force from the reaction member acts on the input member by the change mechanism and the contact between the reaction member and the output member. The ratio between the contact area and the ratio between the input and the main output during the normal operation of the vacuum booster is compared with the ratio of the sum of the input, the main output, and the auxiliary output during the operation of the automatic operation mechanism. Is changed.

According to a second aspect of the present invention, in addition to the function of the first aspect, when the automatic operating mechanism is operated, the change mechanism is configured to change an area of the input member on which the reaction force from the reaction force member acts. Is changed, the ratio between the area of the input member where the reaction force from the reaction member acts and the contact area between the reaction member and the output member is changed.

According to a third aspect of the present invention, in addition to the function of the second aspect, when the automatic operating mechanism is operated, the change mechanism has an area where the reaction force from the reaction force member acts on the input member. Is switched from the area of the first and second contact portions where the reaction force acts in the normal state to the area of the second contact portion, and the area of the input member where the reaction force from the reaction member acts and the reaction force The ratio of the contact area between the member and the output member is changed.

According to a fourth aspect of the present invention, in addition to the function of the third aspect, when the input member is advanced, the first contact portion and the first regulating portion come into contact with each other, so that the input member can be moved. The first and second contact portions move forward integrally with the forward movement of the first position.

On the other hand, when the automatic operating mechanism is operated to generate a second propulsive force on the power piston, the reaction force member is moved to the second propulsion member.
A reaction force corresponding to the thrust is applied to the input member to move the input member rearward, and the input member is moved rearward to shift the valve mechanism from the output increasing operation state to the output holding operation state. . When moving the input member backward,
When the first contact portion contacts the second regulating portion, the backward movement of the first contact portion with respect to the power piston is regulated, and the first contact portion and the second contact portion accompanying the backward movement of the input member are restricted. The backward movement integrally with the contact portion is disabled, and the portion of the input member where the reaction force from the reaction member acts acts as the second contact portion. Therefore, the reaction force from the reaction member in the input member normally acts on the second contact portion from the first and second contact portions in the input member, but with the activation of the automatic operation mechanism, In the input member, the reaction force from the reaction member acts on the second contact portion, and the area of the input member where the reaction force from the reaction member acts and the contact area between the reaction member and the output member Is changed. The negative pressure booster according to claim 5 has, in addition to the operation according to any one of claims 1 to 4, in an initial state of the negative pressure booster, an annular valve seat for controlling the air inflow of the valve seat member. The movable part of the valve member is in contact with the movable part, and the communication between the rear chamber and the atmosphere is shut off. Further, the annular valve seat for air outflow control and the movable portion of the valve member are separated from each other, and the front chamber and the rear chamber are communicated with each other.

When the input member is advanced from the initial state, the valve seat member is also moved forward, and by the advance of the valve seat member, the air release control annular valve seat and the movable portion of the valve member come into contact with each other, and the front chamber The communication between the vehicle and the rear chamber is cut off, and the rear chamber is cut off from the front chamber and the atmosphere to take an output holding action state.

When the input member is advanced from this output holding operation state, the valve seat member is also moved forward, and by the advance of the valve seat member, the annular valve seat for controlling the air inflow is separated from the movable portion and the rear chamber is opened. The rear chamber is cut off from the front chamber by being communicated with the atmosphere, and an output increasing operation state is communicated with the atmosphere.

When the input member is retracted from this output increasing operation state, the valve seat member is also moved rearward, and the retracted valve seat member brings the annular valve seat for air outflow control into contact with the movable portion of the valve member. In this state, the communication between the front chamber and the rear chamber is interrupted, and the output of the rear chamber is shut off from the front chamber and the atmosphere.

When the input member is retracted from the output holding operation state, the valve seat member is also moved rearward, and the retracted valve seat member separates the annular valve seat for air outflow control from the movable portion of the valve member. The initial state is established in which the front chamber and the rear chamber are communicated with each other, the rear chamber is shut off from the atmosphere, and the front chamber and the rear chamber are communicated with each other.

When the automatic operation mechanism is operated by energizing the solenoid coil, the plunger is moved rearward, and the valve seat member is also moved rearward with the rearward movement of the plunger. When the valve seat member moves rearward, the valve seat member abuts on the movable portion to block communication between the front chamber and the rear chamber, and further moves the valve seat member rearward by moving the valve seat member rearward. The movable part is moved away from the air inflow control annular valve seat to communicate the rear chamber with the atmosphere. Therefore, an output increasing operation state is adopted.

When the input member is moved rearward by receiving a reaction force from the reaction member in the output increasing operation state during the normal operation or the operation of the automatic operation mechanism, the input member is retracted, so that the air flows into the atmosphere. The control annular valve seat and the movable part are in contact with each other, the communication between the rear chamber and the atmosphere is cut off, and the output holding action state is adopted in which the rear chamber is cut off from the front chamber and the atmosphere.

The negative pressure type booster according to claim 6 is the same as that of claim 1.
In addition to the operation described in any one of 4 above, in the initial state of the negative pressure booster, the annular valve seat for air inflow control of the valve seat member is in contact with the movable portion of the valve member, and the rear chamber and Communication with the atmosphere is blocked. Further, the annular valve seat for air outflow control and the movable portion of the valve member are separated from each other, and the front chamber and the rear chamber are communicated with each other.

When the input member is advanced from the initial state, the valve seat member is also moved forward, and by the advance of the valve seat member, the air release control annular valve seat and the movable portion of the valve member come into contact with each other, and the front chamber is moved. The communication between the vehicle and the rear chamber is cut off, and the rear chamber is cut off from the front chamber and the atmosphere to take an output holding action state.

When the input member is advanced from this output holding operation state, the valve seat member is also moved forward, and the advance of the valve seat member separates the annular valve seat for air inflow control from the movable portion, and the rear chamber is closed. The rear chamber is cut off from the front chamber by being communicated with the atmosphere, and an output increasing operation state is communicated with the atmosphere.

When the input member is retracted from the output increasing operation state, the valve seat member is also moved rearward, and the retracted valve seat member causes the annular valve seat for air outflow control to come into contact with the movable portion of the valve member. In this state, the communication between the front chamber and the rear chamber is interrupted, and the output of the rear chamber is shut off from the front chamber and the atmosphere.

When the input member is retracted from the output holding operation state, the valve seat member is also moved rearward, and the retracted valve seat member separates the air outlet control annular valve seat from the movable portion of the valve member. The initial state is established in which the front chamber and the rear chamber are communicated with each other, the rear chamber is shut off from the atmosphere, and the front chamber and the rear chamber are communicated with each other.

When the automatic operating mechanism is operated by energizing the solenoid coil, the plunger is moved forward, and the valve seat member is also moved forward as the plunger moves forward. As the valve seat member moves forward, the annular valve seat for air outflow control and the movable portion come into contact with each other, thereby interrupting communication between the front chamber and the rear chamber, and separating the air inflow annular valve seat from the movable portion. Then, the rear chamber and the atmosphere are communicated. Therefore, an output increasing operation state is set.

When the input member is moved rearward by receiving a reaction force from the reaction force member in the output increasing operation state during the normal operation or the operation of the automatic operation mechanism, the valve member is retracted by retreating the input member. The member is also moved rearward, and by retreating the valve seat member, the air-inflow control annular valve seat and the movable portion of the valve member abut, the communication between the rear chamber and the atmosphere is interrupted, and the rear chamber is closed to the front chamber and The output holding action state is cut off from the atmosphere.

According to a seventh aspect of the present invention, in addition to the function of the sixth aspect, when the automatic operation mechanism is operated by energizing the solenoid coil, the plunger is moved forward, and the plunger is moved. With the forward movement, the valve seat member is also moved forward. When the amount of forward movement of the plunger reaches a predetermined amount, the engaging portion of the input member and the engaging portion of the plunger come into contact with each other to regulate the forward movement of the plunger with respect to the input member.

When the input member is moved rearward by receiving a reaction force from the reaction force member in the output increasing operation state during the operation of the automatic operation mechanism, the input member and the valve seat member are brought into contact with each other by the engaging portions. Due to the contact, the valve seat member is also moved rearward when the input member is retracted.

The negative pressure type booster according to claim 8 is the same as that of claim 1.
In addition to the operation described in any one of 4 above, in the initial state of the negative pressure booster, the annular valve seat for air inflow control of the valve seat member is in contact with the movable portion of the valve member, and the rear chamber and Communication with the atmosphere is blocked. Further, the annular valve seat for air outflow control and the movable portion of the valve member are separated from each other, and the front chamber and the rear chamber are communicated with each other.

When the input member is advanced from the initial state, the valve seat member is also moved forward, and by the advance of the valve seat member, the air release control annular valve seat comes into contact with the movable portion of the valve member, and the front chamber The communication between the vehicle and the rear chamber is cut off, and the rear chamber is cut off from the front chamber and the atmosphere to take an output holding action state.

When the input member is advanced from this output holding operation state, the valve seat member is also moved forward, and the advance of the valve seat member separates the annular valve seat for air inflow control from the movable portion, and the rear chamber is opened. The rear chamber is cut off from the front chamber by being communicated with the atmosphere, and an output increasing operation state is communicated with the atmosphere.

When the input member is retracted from the output increasing operation state, the valve seat member is also moved rearward, and by the retreat of the valve seat member, the air release control annular valve seat comes into contact with the movable portion of the valve member. In this state, the communication between the front chamber and the rear chamber is interrupted, and the output of the rear chamber is shut off from the front chamber and the atmosphere.

By retreating the input member from this output holding state, the valve seat member is also moved rearward, and by retreating the valve seat member, the annular valve seat for air outflow control is separated from the movable portion of the valve member. The initial state is established in which the front chamber and the rear chamber are communicated with each other, the rear chamber is shut off from the atmosphere, and the front chamber and the rear chamber are communicated with each other.

As the input member advances and retreats, the automatic operation mechanism also advances and retreats with respect to the power piston.

When the automatic operating mechanism is operated by energizing the solenoid coil, the plunger is moved forward, and the valve seat member is also moved forward with the movement of the plunger forward. As the valve seat member moves forward, the annular valve seat for air outflow control and the movable portion come into contact with each other, thereby interrupting communication between the front chamber and the rear chamber, and separating the air inflow annular valve seat from the movable portion. Then, the rear chamber and the atmosphere are communicated. Therefore, an output increasing operation state is set.

When the input member is moved rearward by receiving a reaction force from the reaction member in the output increasing operation state during the normal operation or the operation of the automatic operation mechanism, the valve seat is retracted by retreating the input member. The member is also moved rearward, and by retreating the valve seat member, the air-inflow control annular valve seat and the movable portion of the valve member abut, the communication between the rear chamber and the atmosphere is interrupted, and the rear chamber is closed to the front chamber and The output holding action state is cut off from the atmosphere.

According to a ninth aspect of the present invention, in addition to the operation of the eighth aspect, when the automatic operating mechanism is operated by energizing the solenoid coil, the plunger is moved forward and the plunger is moved forward. With the forward movement, the valve seat member is also moved forward. When the amount of forward movement of the plunger reaches a predetermined amount, the engaging portion of the input member and the engaging portion of the plunger come into contact with each other to regulate the forward movement of the plunger with respect to the input member.

When the input member is moved rearward by receiving a reaction force from the reaction member in the output increasing state during the operation of the automatic operation mechanism, the input member and the valve seat member come into contact with each other by the engaging portions. Therefore, when the input member is retracted, the valve seat member is also moved rearward.

[0048]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments.

(Embodiment 1) FIG. 1 is a sectional view of a tandem-type negative pressure type brake booster for a vehicle according to an embodiment of the present invention, and FIG. 2 is an enlarged view of a part of FIG. FIG. 3 is an input-output characteristic diagram of the negative pressure brake booster for a vehicle shown in FIGS.

Referring to FIG. 1, a negative pressure type brake booster 10 for a vehicle includes a front shell 11, a rear shell 12, and a partition member 13 between both shells, and has a front pressure chamber and a rear pressure chamber formed therein. A housing 14 is provided.

The front pressure chamber in the housing 14 is provided with a metal front plate 15 and a rubber front diaphragm 16.
A front movable wall 17 made of a metal can be moved forward and backward, and a rear movable wall 20 made of a metal rear plate 18 and a rubber rear diaphragm 19 can be moved forward and backward in the rear pressure chamber. is set up.

The front plate 15 has, at its center, a cylindrical portion 21 which penetrates the center of the partition member 13 in an airtight and slidable manner. The bead portion on the inner peripheral edge of the front diaphragm 16 is the cylindrical portion 2 of the front plate 15.
The bead portion of the outer peripheral edge of the front diaphragm 16 is hermetically sandwiched by the outer peripheral portions of the shells 11 and 12 together with the outer peripheral edge of the partition member 13. I have. The bead portion on the outer peripheral edge of the rear diaphragm 19 is hermetically sandwiched between the folded portion provided on the inner peripheral side of the outer peripheral edge of the partition member 13 and the shell 12. The rear end of the cylindrical portion 21 of the front plate 15 and the inner peripheral edge of the rear plate 18 are provided on the outer periphery of the forward portion of the power piston 22 which penetrates the center of the rear shell 12 in an airtight and slidable manner. The bead portion on the inner peripheral edge of the rear diaphragm 19 is hermetically fixed. Thus, the front pressure chamber in the housing 14 is divided into a front constant pressure chamber 23 as a front chamber and a front variable pressure chamber 24 as a rear chamber, and the rear pressure chamber in the housing 14 is a rear constant pressure chamber as a front chamber. 25 and a rear transformer chamber 26 as a rear chamber.

The front constant pressure chamber 23 is communicated with an engine intake manifold (not shown) as a negative pressure source, and is always kept at a negative pressure. The rear constant pressure chamber 25 is the front plate 1
5 and a groove formed in the outer periphery of the front end of the power piston 22 communicates with the front constant-pressure chamber 23, and thus the rear constant-pressure chamber 25 is always maintained at a negative pressure. The front transformer chamber 24 is the front diaphragm 1
6 is formed in the rear transformer chamber 26 by the groove formed in the inner peripheral surface of the bead portion on the outer peripheral edge, the hole formed in the partition member 13 and the groove formed on the outer peripheral surface of the bead portion on the outer peripheral edge of the rear diaphragm 19. Are in communication.

As shown in FIGS. 1 and 2, an input member 27 is installed inside the power piston 22 so as to be able to move forward and backward with respect to the power piston 22. The input member 27 includes a rear member 28 having a front end located inside the power piston 22 and a rear end located outside the power piston 22, and a power joint 22 connected to a ball joint at the front end of the rear member 28. Central member 2 slidably guided in the front-rear direction (left-right direction in FIG. 2)
9 and a front member 30 whose rear end is screwed to the front end of the central member 29, and is connected to the brake pedal 31 at the rear end of the rear member 28.

The front member 30 has, at its front end, an annular first contact portion 301 and a cylindrical second contact portion 302 which can contact a reaction disk 54 described later. 301, a second contact portion 302 and flange portions 34, 3
And a main unit 30a provided with the main body 5. The second contact portion 302 is inserted into the center hole 301a of the first contact portion 301 so as to be slidable in the axial direction of the center hole 301a (the left-right direction in FIG. 2).

Further, the main body 30a of the front member 30 has a first restricting portion having a diameter larger than the diameter of the second contact portion 302 which is disposed continuously behind the second contact portion 302. Is formed. The shoulder portion 303 defines a retreat limit position of the first contact portion 301 with respect to the second contact portion 302, and further with respect to the main body portion 30a, by abutment of the front portion thereof on the rear surface of the first contact portion 301. .

Input member 27 for power piston 22
A key member 32 for defining the forward limit position and the retreat limit position is provided. The key member 32 is inserted into a radial hole 33 formed in the power piston 22, and is locked to the power piston 22 so as not to drop off from the power piston 22. The thickness of the key member 32 in the front-rear direction is smaller than the size of the radial hole 33 in the front-rear direction, and the key member 32 moves in the front-rear direction by the distance δ shown in FIG. it can. The key member 32 can contact the rear shell 12 at the rear surfaces of both ends protruding to the outer peripheral side of the power piston 22. As shown in FIG. The front wall of the radial hole 33 is in contact with the front surface of the key member 32, and the rear surfaces of both ends of the key member 32 are in contact with the rear shell 12.

The center of the key member 32 is located between a pair of flanges 34 and 35 formed on the outer periphery of the rear end of the front member 30 of the input member 27.
The retreat limit position of the input member 27 with respect to
The rear surface of the key member 32 contacts the front surface of the key member 32 and the key member 32
Is a position where the rear surface of the rear surface abuts against the rear wall of the radial hole 33.
Further, the forward limit position of the input member 27 with respect to the power piston 22 is a position where the front surface of the flange portion 35 contacts the rear surface of the key member 32 and the front surface of the key member 32 contacts the front wall of the radial hole 33. .

Inside the power piston 22, the rear transformer chamber 26 communicates with the front constant pressure chamber 23 and is cut off from the atmosphere in accordance with the movement of the input member 27 in the front-rear direction (left-right direction in FIG. 2) with respect to the power piston 22. A valve mechanism 36 for switching between an output decreasing operation state, an output holding operation state for shutting off the rear variable pressure chamber 26 from the front constant pressure chamber 23 and the atmosphere, and a switching mechanism for cutting off the rear variable pressure 26 from the front constant pressure chamber 23 and an output increasing operation state communicating with the atmosphere. is set up.

The valve mechanism 36 is formed integrally with the center member 29 of the input member 27 and is formed integrally with the air inflow control annular valve seat 37 facing backward and the power piston 22. An air outflow control annular valve seat 38 facing rearward, and an air inflow control annular valve seat 37
And movable portion 41 facing air release control annular valve seat 38
And a fixed portion 43 that is airtightly fixed to the power piston 22 by a retainer 42, and the main component is a cylindrical valve member 45 in which the movable portion 41 is urged forward by a spring 44.

A spring 59 installed between the retainer 58 and the retainer 42 locked to the rear member 28 of the input member 27 urges the input member 27 rearward, and the brake pedal 31 is not depressed. That is, in the initial state shown in FIG. 2, the air inflow control annular valve seat 37 is brought into contact with the movable portion 41 of the valve member 45, and the movable portion 41 is moved from the first air outflow control annular valve seat 38. It is maintained at a distance of a fixed amount g. The power piston 22 is formed with a passage 60 connecting the valve mechanism 36 and the front constant pressure chamber 23 and a passage 61 connecting the valve mechanism 36 and the rear variable pressure chamber 26. An automatic operation mechanism 48 is installed inside the front part of the power piston 22. The automatic operation mechanism 48 includes a valve seat member 40 and a spring 47, a guide member 53, a yoke 50 made of a solenoid coil 49 and a magnetic material, a yoke / reaction disk accommodating member 51 made of a magnetic material, and a plunger 52 made of a magnetic material. It is configured.

The valve seat member 40 is installed on the inner diameter side of the air outflow control annular valve seat 38 so as to be able to advance and retreat with respect to the power piston 22, and is a rearwardly directed auxiliary air outflow control annular valve seat. 39.

An annular seal member 46 for maintaining airtightness between the rear end of the valve seat member 40 and the power piston 22 is attached to the outer periphery of the rear end of the valve seat member 40. The valve seat member 40 is urged forward by a spring 47 provided between the valve seat member 40 and the flange portion 34.

The solenoid coil 49, the yoke 50, and the yoke / reaction disk accommodating member 51 are fixed to the power piston 22, and the plunger 52 contacts the front end surface of the valve seat member 40. The solenoid coil 49 is electrically connected to an electronic control device (not shown) outside the housing 14 by a lead wire. Solenoid coil 49
Is not energized (when the automatic operating mechanism 48 is not operating),
The front end face of the valve seat member 40 is in contact with the plunger 52 by the spring 47, and the front end face of the plunger 52 is fixed to the yoke / reaction disk accommodating member 51. The front end portion, that is, the first contact portion 301 and the second contact portion 302 are held at the position shown in FIG. The annular valve seat 39 is located forward of the air outflow control annular valve seat 38 of the power piston 22 by a distance i.

When the solenoid coil 49 is energized (when the automatic operating mechanism 48 is operated), an electromagnetic attraction is generated between the yoke 50 and the plunger 52, and the plunger 52 causes the valve seat member 40 to move by the electromagnetic attraction. It is retracted against the spring 47. The retreat amount of the valve seat member 40 is the yoke 50
When the valve seat member 40 is retracted, the auxiliary air outlet control annular valve seat 39 of the valve seat member 40 corresponds to the distance f between the power piston 22 and the plunger 52. It is located behind 38.

Inside the yoke / reaction disk accommodating member 51, a reaction disk 5 as a disk-shaped reaction member made of rubber is provided in front of the guide member 53.
A rear end portion 56 of an output rod 55 that penetrates the center of the front wall of the housing 14 in an airtight and slidable manner is slidably provided on the front side of the reaction disk 54. I have. As is well known, the reaction disk 54 transmits the propulsive force of the power piston 22 and the forward force of the input member 27 to the output rod 55, and at the same time, applies a reaction force of a magnitude corresponding to the propulsive force of the power piston 22 to the input member 27. It is provided so as to retreat.

In the initial state, the guide member 53 has the first
A contact surface 531 is provided as a second regulating portion that is separated from the rear surface of the contact portion 301 by a distance of a predetermined amount e. Contact surface 5
The rear end of the first contact portion 301 with respect to the power piston 22 is brought into contact with the first contact portion 301 when the input member 27 moves rearward when the automatic operation mechanism 48 described later is operated. Restrict movement to.

Each predetermined amount e in the initial state shown in FIG.
The relationship between f, g, and i is set so that e + g + i ≦ f.

In the center of the front constant pressure chamber 23, a return spring 57 for retreating the power piston 22 and the movable walls 17, 20 connected thereto with respect to the housing 14 is provided.

The output rod 55 is operatively connected to a piston (not shown) of a master cylinder (not shown).

As is clear from FIG. 2, the front surface of the first contact portion 301 has an area of πc ² −πb ² (first area), and the first contact portion 301 is The rear surface of the reaction disk 54 can be brought into contact with the second contact portion 3.
2, the front surface has an area of πb ² (second area), and the second contact portion 302 can contact the rear surface of the reaction disk 54 at this front surface. ing. The front end of the input member 27, that is, the front surfaces of the first contact portion 301 and the second contact portion 302 and the rear surface of the reaction disk 54 are separated from each other by a predetermined amount a in the initial state shown in FIG. I have.

As shown in FIG. 2, the rear end 56 of the output rod 55 has a rear surface having an area of πd ² , and the output rod 55 is connected to the rear surface of the rear end 56 by the front surface of the reaction disk 54. Abut.

Next, the operation will be described. The state shown in FIGS. 1 and 2 is a state in which the brake pedal 31 is not depressed and the automatic operation mechanism 48 is not operated, and the valve mechanism 3
6 communicates the rear variable pressure chamber 26 with the front constant pressure chamber 23 and cuts off from the atmosphere, that is, the output reduction action state, that is, the air inflow control annular valve seat 37 abuts the movable portion 41 of the valve member 45 and the movable portion 41 1, the pressure in the front and rear variable pressure chambers 24 and 26 is reduced to the same pressure as the pressure in the front constant pressure chamber 23. Piston 22
No forward force acts on the power piston 22 and the movable walls 17 and 20 connected to the power piston 22
As a result, the front wall of the radial hole 33 of the power piston 22 is moved to the retreat limit position with respect to the housing 14,
2 and is held at a position where the rear surfaces of both ends of the key member 32 are in contact with the rear shell 12.

As shown in FIGS. 1 to 3, when the driver depresses the brake pedal 31 for the normal braking operation, the input member 27 advances with respect to the power piston 22, and the movable portion 41 of the valve member 45 The rear variable pressure chamber 26 is cut off from the front constant pressure chamber 23 by abutting on the air outflow control annular valve seat 38 of the piston 22. That is, the valve mechanism 36 switches from the output decreasing operation state to the output holding operation state. When the input member 27 moves forward, the rear surface of the first contact portion 301 is in contact with the front surface of the shoulder portion 303. Therefore, the first contact portion 301 and the main body 30a, in other words, the first contact portion. Part 30
The first and second contact portions 302 move integrally forward.

When the input member 27 advances, the front end face of the input member 27, that is, the first and second contact portions 301 and 302,
A gap remains between the front surface of the reaction disk 54 and the rear surface of the reaction disk 54, and this gap is substantially equal to a-g.
The rear surface of the first contact portion 301 and the contact surface 531 are substantially e +
g.

Next, the input member 2 is switched from the output holding operation state.
7 further moves forward by the distance of α, the air inflow control annular valve seat 37 is separated from the movable portion 41 of the valve member 45 to communicate the rear transformer chamber 26 with the atmosphere, and the valve mechanism 36 enters the output increasing operation state. Switch. Therefore, the atmosphere flows into the rear transformer chamber 26, further flows into the front transformer chamber 24 from the rear transformer chamber 26, and the pressure in both the transformer chambers 24 and 26 rises. A forward force is generated by the pressure difference between the chamber 24 and a forward force is generated by the pressure difference between the rear constant pressure chamber 25 and the rear variable pressure chamber 26 on the rear movable wall 20, and the front constant pressure chamber 23 and the rear A forward force is generated due to a pressure difference between the pressure change chamber 26 and the forward pressure, and these forward forces are transmitted from the power piston 22 to the automatic operation mechanism 48.
Is transmitted to the output rod 55 via the yoke / reaction disk accommodating member 51, the guide member 53, and the reaction disk 54, and the movable walls 17, 20, the power piston 22, and the output rod 55 advance integrally with the housing 14. Then, the operation of the master cylinder is started.

At this time, the power piston 22 is connected to the input member 2
7, the movable portion 41 of the valve member 45 approaches the air inflow control annular valve seat 37. In addition, the reaction disk 54 reduces a gap of approximately ag-α between the rear surface of the center portion and the front end surface of the input member 27, that is, the first and second contact portions 301 and 302. After entering the guide member 53 and abutting against the front surfaces of the first and second contact portions 301 and 302, the reaction disk 54 applies the forward force of the power piston 22 and the forward force of the input member 27 to the output rod 5.
5 and a reaction force corresponding to the propulsive force from the power piston 22 is applied to the input member 27 so that the input member 27 is retracted with respect to the power piston 22. The input member 27 is a reaction disk 54
In the state in which the power piston 22 is to be moved rearward by receiving a reaction force, there is a gap of approximately e + g + α between the rear surface of the first contact portion 301 and the contact surface 531. I have.

The advancement of the power piston 22 with respect to the housing 14 and the reaction disk 54 of the input member 27
As the power piston 22 moves forward with respect to the input member 27 due to the retraction with respect to the power piston 22, the movable portion 41 of the valve member 45 eventually comes into contact with the air inflow control annular valve seat 37 again, and the variable pressure chamber 24, The flow of the atmosphere into the air pump 26 is stopped (the valve mechanism 36 is switched to the output holding operation state). At this time, the input member 27 moves rearward by less than approximately e + g + α, in other words, approximately α, with respect to the power piston 22 by receiving the reaction force from the reaction disk 22, and accordingly, the first contact portion. 301 does not come into contact with the contact surface 531. That is, in the rearward movement of the input member 27, the first contact portion 301
And the second contact portion 302 move backward integrally.

In the normal braking operation, the input applied from the brake pedal 31 to the input member 27 is the value Fi1 shown in FIG. 3, and the output applied from the output rod 27 to the master cylinder is shown in FIG. Value Fo1
It is. That is, the first propulsive force of the power piston 22 generated by the brake operation at the input Fi1 is output to the outside of the device as the main output Fo1 via the output rod 55.

When the input applied from the brake pedal 31 to the input member 27 is increased to a value less than the value Fi3 in FIG. 3, the input member 27 moves forward with respect to the power piston 22 and the annular valve seat 37 for controlling the air inflow. Is again separated from the movable portion 41 of the valve member 45 (the valve mechanism 36 is switched to the output increasing operation state), the atmosphere flows into the variable pressure chambers 24, 26, and the pressure in the variable pressure chambers 24, 26 increases, and the movable wall 17, 20 and the forward force of the power piston 22 are increased, and the movable walls 17, 20,
Power piston 22 and output rod 55 are in housing 1
Going further for 4. Further, when the power piston 22 advances with respect to the input member 27, the movable portion 41 of the valve member 45 approaches the air inflow control annular valve seat 37, and the movable portion 41 of the valve member 45 eventually becomes the air inflow control annular valve. Seat 3
7 again to stop the inflow of air into the transformation chambers 24, 26 (the valve mechanism 36 switches to the output holding operation state),
The forward force between the movable walls 17, 20 and the power piston 22 stops increasing.

When the input applied from the brake pedal 31 to the input member 27 is reduced to a value larger than the value Fi1 in FIG. 3, the input member 27 is retracted with respect to the power piston 22 and the movable portion 41 of the valve member 45 is moved. Is power piston 2
2, the movable portion 41 is separated from the first annular valve seat 38 for controlling the outflow of air (the valve mechanism 36 is switched to the output reducing operation state), and the variable pressure chambers 24 and 26 are connected to the front constant pressure chamber 23. The atmosphere in the transformer chambers 24 and 26 is discharged through the constant pressure chamber 23 by the negative pressure source, and the transformer chambers 24 and 26 are discharged.
Of the movable wall 17, 20 and the power piston 2
2, the movable walls 17, 20, the power piston 22, and the output rod 55 are retracted with respect to the housing 14. At that time, the power piston 22 also retreats with respect to the input member 27, the air outflow control annular valve seat 38 approaches the movable portion 41 of the valve member 45, and the air outflow control annular valve seat 38 is eventually moved to the valve member 45. Abuts the movable part 41 of the transformer chamber 2
The outflow of the air from the airbags 4 and 26 is stopped (the valve mechanism 36 is switched to the output holding state), and the reduction of the forward force of the movable walls 17 and 20 and the power piston 22 is stopped.

The input value Fi3 shown in FIG.
Input values at which the pressures of the pressures 4 and 26 become the atmospheric pressure are shown. When the input is in the range from the value Fi1 to the value Fi3, the output rod 55
The amount of change in the output applied to the master cylinder is larger than the amount of change in the input applied to the input member 27. The ratio of the output to the input, in other words, the ratio between the amount of change in the input applied to the input member 27 and the amount of change in the main output output from the output rod 55 according to the amount of change in the input, that is, as shown in FIG. The inclination from the input Fi1 to Fi3 in the characteristic line at the time of the normal braking action is caused by the first and second contact portions 3 of the input member 27 on which the reaction force from the reaction disk 54 acts.
The ratio of the contact area between the rear surface of the rear end portion 56 of the output rod 55 and the front surface of the reaction disk 54 to the area of the front surfaces of the front and rear surfaces 01 and 302 coincides with the ratio.

In FIG. 3, when the input is the value Fi3, the output is the value Fo4. If the input is further increased from the value Fi3, the output increases by the increment of the input. In FIG. 3, the amount of change in force per unit length on the vertical axis is larger than the amount of change in force per unit length on the horizontal axis. If the change in force per unit length on the vertical axis and the change in force per unit length on the horizontal axis are drawn to match, the input is the value Fi.
The line indicating the input-output correlation when the value is larger than 3 has a slope of 45 degrees.

When the brake pedal 31 is depressed and the input member 27, the movable walls 17, 20, the power piston 22 and the output rod 55 are advanced with respect to the housing 14, the key member 32 is separated from the rear shell 12. doing. When the driver releases the brake pedal 31 to release the normal braking action, the rear surface of the flange portion 34 is moved by the input member 27 against the power piston 22 by the reaction force applied from the reaction disk 54 and the spring 59. The key member 32 is retracted to a position in contact with the front surface. As a result, the movable portion 41 of the valve member 45 is retracted with respect to the power piston 22, the movable portion 41 is separated from the atmospheric outflow control annular valve seat 38 (the valve mechanism 36 is switched to the output reducing operation state), and the pressure is changed. The atmosphere in the chambers 24 and 26 is quickly exhausted by the negative pressure source via the constant pressure chamber 23, and the input member 27, the movable walls 17, 20 and the power piston 22 The output rod 55 is quickly retracted with respect to the housing 14.

When the input member 27, the movable walls 17, 20, the power piston 22, and the output rod 55 are retracted with respect to the housing 14, the key member 32 is eventually moved to the rear shell 12 by the key member 32.
, And the retreat of the input member 27 with respect to the housing 14 is stopped. On the other hand, when the movable walls 17, 20, the power piston 22, and the output rod 55 are retracted with respect to the housing 14, the power piston 22 is at the retreat limit position with respect to the housing 14, that is, the front side wall of the radial hole 33 of the power piston 22 is a key member. 32, and continues to the position where the rear surfaces of both ends of the key member 32 abut the rear shell 12. As a result, the air outflow control annular valve seat 38 of the power piston 22 approaches the movable portion 41 of the valve member 45, and a small gap of g exists between the air outflow control annular valve seat 38 and the movable portion 41. Inactive. Because the gap between the air release control annular valve seat 38 and the movable portion 41 is small, the valve mechanism 36 switches from the output decreasing operation state to the output increasing operation state through the output holding operation state at the next operation. The required amount of advance of the input member 27 is small, and therefore, the play when the brake pedal 31 is depressed is small, and the responsiveness is good.

The reaction disk 54 is restored to the state shown in FIG. 2 by its own elasticity due to a decrease in the force transmitted between the power piston 22 and the output rod 55.

Next, when the driver rapidly depresses the brake pedal 31 with the input Fi1 for the emergency braking action,
The input member 27 moves forward with respect to the power piston 22, and the movable portion 41 of the valve member 45 contacts the first air release control annular valve seat 38 of the power piston 22 to move the rear variable pressure chamber 26 from the front constant pressure chamber 23. Cut off. That is, the valve mechanism 36
Is switched from the output decreasing operation state to the output holding operation state.

When the input member 27 advances, the front end face of the input member 27, that is, the first and second contact portions 301 and 302 are provided.
A gap remains between the front surface of the reaction disk 54 and the rear surface of the reaction disk 54, and this gap is substantially equal to a-g.
The rear surface of the first contact portion 301 and the contact portion 531 are substantially e +
g.

Next, as the input member 27 is further advanced by the distance α, the air inflow control annular valve seat 37 is moved to the valve member 45.
The variable pressure chamber 26 is separated from the movable portion 41, and communicates with the atmosphere, and the valve mechanism 36 switches to the output increasing operation state. In parallel with the operation of the brake pedal 31, the electronic control unit energizes the solenoid coil 49, so that the automatic operation mechanism 48 is operated.

When the solenoid coil 49 is energized, an electromagnetic attraction force is generated between the plunger 52 and the yoke 50, and the plunger 52 is retracted with respect to the power piston 22, and the valve seat member 40 is retracted by the distance f. , Valve seat member 4
The zero outflow control annular valve seat 39 is in contact with the movable portion 41 of the valve member 45, and the valve seat member 40 moves the movable portion 41 backward with respect to the power piston 22. By such an operation, the movable portion 41 of the valve member 45 is separated from the air outlet control annular valve seat 38 of the power piston 22, but the auxiliary air outlet control annular valve seat 39 of the valve seat member 40 is moved by the movable portion 41. And the variable pressure chambers 24 and 26 and the constant pressure chamber 23
The gap between the air inflow control annular valve seat 37 and the movable portion 41 of the valve member 45 is changed from α to α while the cutoff state is maintained.
+ Fi is increased by the distance.

Accordingly, the operation of the brake pedal 31 and the operation of the automatic operation mechanism 48 allow the atmosphere to be quickly removed from the transformation chamber 2.
4, the pressure in the transformation chambers 24, 26 rapidly rises, and the movable walls 17, 20, the power piston 22, and the output rod 55 advance quickly with respect to the housing 14.

When the power piston 22 advances with respect to the housing 14, the power piston 22 also advances with respect to the input member 27.
Approaches the air inflow control annular valve seat 37. In addition, the advance of the power piston 22 causes the reaction disc 54
Inside the guide member 53 so as to reduce a gap that is substantially ag-α between the rear surface of the central portion and the front end surface of the input member 27, that is, the first and second contact portions 301 and 302. And the reaction disk 54 contacts the front surfaces of the first and second contact portions 301 and 302 to transmit the forward force of the power piston 22 and the forward force of the input member 27 to the output rod 55, and from the output rod 55. The reaction force corresponding to the output of
The input member 27 is provided so as to be retracted with respect to the power piston 22. In a state where the input member 27 is to be moved rearward with respect to the power piston 22 by receiving the reaction force from the reaction disk 54, the rear surface of the first contact portion 301 and the contact surface 531
And a gap of approximately e + g + α is present between them.

The input member 27 receives the reaction force from the reaction disk 54 and
The input member 27 is moved backward by a distance of approximately α + fi with respect to the first contact portion 301.
The gap of approximately e + g + α between the rear surface and the contact surface 531 is 0 as can be seen from the fact that e + g ≦ f is set in the initial state. That is, the first contact portion 30
1 and the contact surface 531 are in contact with each other.

Since the rear surface of the first contact portion 301 comes into contact with the contact surface 531, the first contact portion 301 moves backward integrally with the main body portion 30 a and thus with the second contact portion 302, that is, , The rearward movement with respect to the power piston 22 is restricted. Since the rearward movement of the first contact portion 301 is restricted, the reaction disk 54 can no longer move the first contact portion 301 rearward, and the reaction force from the reaction disk 54 at the input member 27 is no longer available. The contact surface on which is applied is only the front surface of the second contact portion 302. The reaction disk 54 enters the center hole 301a of the first contact portion 301 and acts only on the front surface of the second contact portion 302, and moves the input member 27 except the first contact portion 301 to the rear side.

When the power piston 22 advances with respect to the input member 27 due to the advancement of the power piston 22 with respect to the housing 14 and the retraction of the input member 27 with respect to the power piston 22, the movable portion 41 is eventually moved to the annular valve seat 37. And the valve mechanism 36 enters the output holding operation state. In this case, the longitudinal position of the input member 27 with respect to the power piston 22 with respect to the longitudinal position at the same time in the normal braking operation is determined from the displacement f in FIG. It has shifted rearward by a distance obtained by subtracting the distance i from the annular valve seat 39, and the amount of the reaction disc 54 entering the inside of the guide member 53 is larger than the amount of entry during normal braking. That is, the forward force transmitted from the power piston 22 to the output rod 55 via the reaction disk 54 (output applied from the output rod 55 to the master cylinder) is larger than that during normal braking. The value is the middle value Fo2. In other words, the first propulsive force of the power piston 22 generated by the brake operation at the input Fi1 is exerted as the output Fo1 via the output rod 55. However, when the automatic operation mechanism 48 is activated, the power piston 22 is actuated. Generates a second propulsion force, and an auxiliary output of [Fo2-Fol] is added to the output rod 55, so that the brake booster 1
0, the main output Fo1 and the auxiliary output [Fo2-Fo1]
Will be output.

Transformation chamber 2 when output is value Fo2 in FIG.
The pressure at 4,26 is lower than atmospheric pressure. Accordingly, when the input applied to the input member 27 is increased by a value less than the value Fi2 in FIG. 3, the input member 27 excluding the first contact portion 301 is advanced with respect to the power piston 22 and the valve mechanism 36 outputs The state is switched from the holding operation state to the output increasing operation state, and the pressure in the transformation chambers 24 and 26 increases to increase the output. And
When the power piston 22 advances with respect to the input member 27 other than the first contact portion 301, the valve mechanism 36 switches from the output increasing operation state to the output holding operation state, and the increase in output stops.

When the input of the input member 27 is reduced, the input member 27 excluding the first contact portion 301 is moved by the reaction force from the reaction disk 54 to the power piston 22.
, And is switched to a state where the output of the valve mechanism 36 is reduced, and the pressure in the transformation chambers 24 and 26 is reduced to reduce the output. Then, when the power piston 22 retreats with respect to the input member 27, the valve mechanism 36 is switched from the output decreasing operation state to the output holding operation state, and the decrease in output stops.

The output value Fo3 in FIG. 3 indicates the value when the pressure in the transformation chambers 24 and 26 has increased to the atmospheric pressure, and the input at this time is the value Fi2. The input is the value Fi1 and the value F
i2, the ratio of the output to the input, in other words, the amount of change in the input applied to the input member 27, and the main output and the auxiliary output from the output rod 55 corresponding to the amount of change in the input. The ratio of the total output to the change amount of the total output, that is, the inclination from the input Fi1 to Fi2 in the characteristic line at the time of the emergency braking operation shown in FIG. The ratio is equal to the ratio of the area of the front surface of the reaction rod 54 to the rear surface of the rear end 56 of the output rod 55 with respect to the area of the front surface of the second contact portion 302. In the range where the input is larger than the value Fi2, the output changes by the change of the input.

When the driver releases the brake pedal 31 while the solenoid coil 49 is energized, the input member 2 is released in the same manner as when the brake pedal 31 is released during the normal braking operation.
7 is retracted with respect to the power piston 22 by the reaction force applied from the reaction disk 54 and the spring 59. As a result, the valve mechanism 36 is switched to the output reducing operation state, the pressure in the variable pressure chambers 24, 26 is reduced, and the output is reduced. As a result, the input member 27, the movable wall 17,
0, the power piston 22 and the output rod 55 are retracted with respect to the housing 14, and eventually return to the inactive state shown in FIGS.

When the condition for de-energizing the solenoid coil 49 is satisfied, the electronic control unit sets the solenoid coil 49
Is de-energized. Thereby, the valve seat member 40 and the plunger 52 are returned to the position shown in FIG. 2 by the biasing spring 47, and the operation of the automatic operation mechanism 48 is completed.

As described above, according to the vacuum booster 10 of the present embodiment, the input / output ratio at the time of the normal braking operation shown in FIG. The contact area πc ² between the front surface of the reaction disk 54 and the rear surface of the reaction disk 54 is determined by the ratio of the contact area πc ² between the front surface of the reaction disk 54 and the rear surface 56 of the output rod 54. The input / output ratio at the time of the emergency brake operation in which the automatic operation mechanism 48 is operated is determined by the contact area πb ² between the front surface of the second contact portion 302 and the rear surface of the reaction disk 54 and the rear surface of the rear end portion 56 of the output rod 54. And the contact area πd ² between the reaction disk 54 and the front surface of the reaction disk 54. The input / output ratio at the time of operation of the automatic operation mechanism 48 in the present embodiment is set larger than the input / output ratio at the time of normal operation.

The input / output ratio during the emergency brake operation can be changed by appropriately setting the area of the front surface of the second contact portion 302.

Further, when the input / output ratio at the time of the emergency braking operation is made larger than the input / output ratio at the time of the normal braking operation, in the negative pressure type booster 10 of the present embodiment, the movement amount f of the plunger 52 is increased. Since there is no need to perform this operation, it is not necessary to increase the size of the automatic operation mechanism 48.

Furthermore, in the conventional negative pressure type booster,
Although the input member may be increased in size by disposing the elastic member on the input member, it is necessary to dispose the elastic member or the like on the input member 27 in the negative pressure type brake booster 10 of the present embodiment. Since there is no input member 27, there is no possibility that the input member 27 becomes large.

Therefore, it is possible to provide the negative pressure type brake booster 10 which can be downsized.

(Embodiment 2) FIG. 4 is a sectional view showing the vicinity of a valve mechanism and an automatic operation mechanism of a tandem-type vehicle brake booster according to an embodiment of the present invention. The same members as those in the first embodiment are denoted by the same reference numerals. Except for the input member 27, the valve mechanism 36, and the automatic operation mechanism 48, the configuration is substantially the same as that of the first embodiment, and thus the description is omitted.

The input member 27 has a rear member 28, a rear end connected by a ball joint at the front end of the rear member 28, a central member 29 directly slidably supported by the power piston 22, and a rear end. A front member 30 is screwed and fixed to the front end of the central member 29, and is connected to a brake pedal (not shown) at the rear end of the rear member 28.

The front member 30 has, at its front end, an annular first contact portion 301 and a cylindrical second contact portion 302 which can contact a reaction disk 54 described later. The main body 30a includes a first contact portion 301 and a second contact portion 302 and a flange portion 34. 2nd contact part 3
Reference numeral 02 is inserted into the center hole 301a of the first contact portion 301 so as to be slidable in the axial direction of the center hole 301a (the left-right direction in FIG. 4).

The main body 30a of the front member 30 has a first regulating portion having a diameter larger than the diameter of the second contact portion 302 which is disposed continuously behind the second contact portion 302. Is formed. The shoulder portion 303 defines a retreat limit position of the first contact portion 301 with respect to the second contact portion 302, and further with respect to the main body portion 30a, by abutment of the front portion thereof on the rear surface of the first contact portion 301. .

Input member 27 for power piston 22
A key member 32 for defining the forward limit position and the retreat limit position is provided. The central portion of the key member 32 is located between the flange portion 34 of the front member 30 and the front end of the central member 29. Input member 2 for power piston 22
The forward and backward limit positions of the input member 27 and the backward limit position of the input member 27 with respect to the housing 14 are the same as those of the first embodiment. Passages 60 and 61 are provided in the power piston 22.
Are formed.

The valve mechanism 36 is provided so as to be able to move forward and backward with respect to the input member 27 and the power piston 22, and has a valve seat member 40 having an air inflow control annular valve seat 37 facing rearward. An air outflow control annular valve seat 38 formed integrally with the power piston 22 and facing rearward; a movable portion 41 opposed to the air inflow control annular valve seat 37 and the air outflow control annular valve seat 38; Retainer 4
2 and a fixed portion 43 which is hermetically fixed to the power piston 22 by the
4 and a cylindrical valve member 45 urged forward by 4. On the outer periphery of the central member 29 of the input member 27, a seal member 7 for maintaining airtightness between the central member 29 and the valve seat member 40 is provided.
0 is attached.

An automatic operating mechanism 48 is provided inside the front part of the power piston 22. The automatic operation mechanism 48 includes a solenoid coil 49 fixed to the power piston 22, a yoke 50 made of a magnetic material, a yoke / reaction disk accommodating member 51, and a plunger 52 made of a magnetic material.

The solenoid coil 49 is electrically connected to an electronic control unit outside the housing 14 by a lead wire. The rear end of the plunger 52 is connected to the front end of the valve seat member 40. When the solenoid coil 49 is energized, that is, when the automatic operation mechanism 48 is operated, an electromagnetic attraction force is generated between the yoke / reaction disk housing member 51 and the plunger 52.

When the automatic operation mechanism 48 is not operated, the valve seat member 4
A spring for urging the valve seat member 40 rearward with respect to the input member 27 to position the valve seat member 40 with respect to the input member 27 so as to move the valve seat member 40 forward and backward integrally with the input member 27 at the retreat limit position with respect to the input member 27. 72 is provided between the central member 29 of the input member 27 and the valve seat member 40, and an opposing contact portion is formed by the inner peripheral rear end 52 a of the plunger 52 and the front surface of the flange portion 34 of the input member 27. Have been.

When the automatic operation mechanism 48 operates, the valve seat member 40
Is located at a forward position with respect to the input member 27, and the valve seat member 40 and the central member 29 are connected to the automatic operating mechanism 4 in this forward position so that the two can be integrally retracted.
8 which are in contact with each other when actuated
a.

The front end 52b of the plunger 52 and the yoke 51
And the rear end 51b constitute an opposing contact portion.

The yoke / reaction disk accommodating member 5
1 accommodates the reaction disk 54 at the front side thereof, and guides the main body 30a and the first and second contact portions 301 and 302 slidably at the rear side thereof. In the initial state, the yoke / reaction disk accommodating member 51 is provided with a contact surface 51a as a second regulating portion which is separated from the rear surface of the first contact portion 301 by a distance of a predetermined amount e. The contact surface 51a is used by the first contact portion 30 when the input member 27 moves rearward when the automatic operation mechanism 48 described later is operated.
The contact of the first contact portion 301 with the power piston 22 prevents the first contact portion 301 from moving rearward.

The yoke / reaction disk accommodating member 5
The first rear end 51b and the front end 52b of the plunger 52 are separated by a predetermined distance f when the automatic operation mechanism 48 is not operated, that is, in the state of FIG. Also, the engaging portions 40a, 2
9a is separated by a predetermined amount f when the automatic operation mechanism 48 is not operated, that is, in the state of FIG.

In the initial state shown in FIG. 4, the air inlet control annular valve seat 37 is brought into contact with the movable portion 41 of the valve member 45, and the movable portion 41 is connected to the first air outflow control annular valve seat 3.
8 and a predetermined amount g of distance separation.

Each predetermined amount e in the initial state shown in FIG.
The relationship between f and g is set so that e + g ≦ f.

The urging force of the spring 72 is
Greater than the biasing force. Then, the distance f shown in FIG.
h is greater than distance g.

The input-output characteristics of the embodiment of FIG. 4 are the same as the characteristics of FIG. 3, and the operation will be described with reference to FIGS. 4 shows a non-operating state in which the normal braking operation and the emergency braking operation are not performed. The input member 27 is located at the retreat limit position with respect to the housing 14, and the movable walls 17, 20 and the power piston 22 and the output The rod 55 is located at the retreat limit position with respect to the housing 14, and the valve mechanism 36 is configured such that the air inflow control annular valve seat 37 of the valve seat member 40 which is located at the retreat limit position with respect to the input member 27 is a movable part of the valve member 45. 41, in which the movable portion 41 is separated from the annular valve seat 38 for controlling the outflow of the air of the power piston 22, that is, in a state where the output is reduced.
The pressures of the pressure chambers 4 and 26 are equal to the pressures of the constant pressure chambers 23 and 24.

When the driver depresses the brake pedal to apply an input to the input member 27 for normal braking action, the flange portion 34 of the input member 27 and the inner peripheral rear end portion 52a of the plunger 52 are engaged. , The input member 27, the plunger 52 and the valve seat member 40 are integrally advanced with respect to the power piston 22, and the movable portion 41 of the valve member 45 is moved to the air outlet control annular valve seat 3 of the power piston 22.
8, the valve mechanism 36 is switched to the output holding operation state. At this time, the first contact portion 301 and the second contact portion 30
A gap remains between the reaction disk 2 and the reaction disk 54, and this gap is substantially equal to a-g. The rear surface of the first contact portion 301 and the contact surface 51a are separated from each other by a distance of substantially e + g.

Next, the input member 2 is moved from the output holding operation state.
7 further moves forward by the distance of α, the air inflow control annular valve seat 37 is separated from the movable portion 41, the valve mechanism 36 is switched to the output increasing operation state, and the air flows into the transformer chambers 24, 26. The pressure in the transformation chambers 24 and 26 rises,
20, the power piston 22, and the output rod 55 integrally start to advance with respect to the housing 14.

At this time, the power piston 22 is connected to the input member 2
7, the movable portion 41 of the valve member 45 approaches the air inflow control annular valve seat 37. In addition, the reaction disk 54 reduces a gap of approximately ag-α between the rear surface of the center portion and the front end surface of the input member 27, that is, the first and second contact portions 301 and 302. After entering the guide member 51 and abutting against the front surfaces of the first and second contact portions 301 and 302, the reaction disk 54 applies the forward force of the power piston 22 and the forward force of the input member 27 to the output rod 5.
5 and a reaction force corresponding to the propulsive force of the power piston 22 is applied to the input member 27 so that the input member 27 is retracted with respect to the power piston 22. In a state where the input member 27 is receiving a reaction force from the reaction disk 54 and is to be moved rearward with respect to the power piston 22, there is substantially no space between the rear surface of the first contact portion 301 and the contact surface 51 a. There is a gap of e + g + α.

When the power piston 22 advances with respect to the input member 27, the movable part 4 of the valve member 45 is eventually formed.
1 again comes into contact with the annular valve seat 37 for controlling the inflow of air into the variable pressure chamber 2.
The flow of air into the air conditioners 4 and 26 is stopped (the valve mechanism 36 is switched to the output holding state). At this time, the input member 27 is moving backward with respect to the power piston 22 by less than approximately e + g + α, in other words, approximately α.
Therefore, the first contact portion 301 does not contact the contact surface 51a. That is, when the input member 27 moves backward, the first contact portion 301 and the second contact portion 302 move backward integrally. In this normal braking operation, the input applied from the brake pedal to the input member 27 is the value Fi1 shown in FIG. 3, and the output given from the output rod 27 to the master cylinder is the value Fo1 shown in FIG.
It is. That is, the first propulsive force of the power piston 22 generated by the brake operation at the input Fi1 is output to the outside of the device as the main output Fo1 via the output rod 55.

Thereafter, as the input applied to the input member 27 is increased or decreased between the value Fi1 and the value Fi3 in FIG. 3, the valve mechanism 36 is switched between the output increasing operation state, the output holding operation state, and the output decreasing state. By switching the input value F
Output values Fo1 to Fo4 having magnitudes corresponding to i1 to Fi3
Is output from the output rod 55. If the input is Fi3
When it is increased above, the output increases by the amount of the input.

The input applied to the input member 27 is the value Fi1.
In the above case, the reaction force is applied from the reaction disk 54 to the first and second contact portions 30 as in the embodiment of FIGS.
1, 302, the input member 27 is provided.

When the input applied to the input member 27 is removed, the input member 27 is retracted with respect to the power piston 22 by the reaction force applied to the input member 27 from the reaction disk 54 and the spring 59, and the valve mechanism is actuated. 36 is switched to the output reduction operation state, the atmosphere in the transformation chambers 24 and 26 is exhausted, and the pressure in the transformation chambers 24 and 26 is reduced. Is integrated into the housing 1
4 starts retreating, and finally returns to the position of FIG.

The ratio of the output to the input when the input is Fi1 to Fi3, in other words, the change in the input applied to the input member 27 and the output rod 5 corresponding to the change in the input.
5 is the ratio of the change of the main output to the output, that is, the input Fi1 to F1 in the characteristic line at the time of the normal braking operation shown in FIG.
The inclination at i3 is caused by the first and second contact portions 301, 3 of the input member 27 to which the reaction force from the reaction disk 54 acts.
02 of the output rod 55 with respect to the area of the front surface
And the ratio of the contact area between the rear surface and the front surface of the reaction disk 54.

Next, when the driver rapidly depresses the brake pedal with the input Fi1 (FIG. 3) for the emergency braking action, the input member 27 advances with respect to the power piston 22, and the movable portion of the valve member 45 moves. 41 abuts on the first air outflow control annular valve seat 38 of the power piston 22 to shut off the rear variable pressure chamber 26 from the front constant pressure chamber 23. That is, the valve mechanism 36 switches from the output decreasing operation state to the output holding operation state.

When the input member 27 advances, the front end face of the input member 27, that is, the first and second contact portions 301 and 302 are provided.
A gap remains between the front surface of the reaction disk 54 and the rear surface of the reaction disk 54, and this gap is substantially equal to a-g.
The rear surface of the first contact portion 301 and the contact surface 51a are substantially e +
g.

Then, as the input member 27 is further advanced by the distance α, the air inflow control annular valve seat 37 is moved to the valve member 45.
The variable pressure chamber 26 is separated from the movable portion 41, and communicates with the atmosphere, and the valve mechanism 36 switches to the output increasing operation state. In parallel with the operation of the brake pedal 31, the electronic control unit energizes the solenoid coil 49, so that the automatic operation mechanism 48 is operated.

When the solenoid coil 49 is energized, an electromagnetic attractive force is generated between the plunger 52 and the yoke / reaction disk accommodating member 51, and the plunger 52 is advanced with respect to the power piston 22 to move the valve seat member 40. By moving the valve seat member 40 forward by the distance f, the air outlet control annular valve seat 37 of the valve seat member 40 is further separated from the movable portion 41 of the valve member 45 from the separation amount α to α + f. As the plunger 52 and the valve seat member 40 advance, the front end portion 52b of the plunger 52 comes into contact with the rear end portion 51b of the yoke / reaction disk housing member 51, and the engaging portion 40a of the valve seat member 40 It comes into contact with the engagement portion 29a and regulates the forward movement of the valve seat member 40 with respect to the input member 27. With such an operation, the annular valve seat 37 for controlling the air inflow is provided.
The gap between the movable part 41 of the valve member 45 and the movable part 41 is increased to the maximum amount. Therefore, by the operation of the brake pedal and the operation of the automatic operation mechanism 48, the air quickly flows into the transformation chambers 24, 26, and the pressure in the transformation chambers 24, 26 rapidly rises, and the movable walls 17, 20 and the power piston 22 And output rod 55
Advances rapidly with respect to the housing 14.

The movable walls 17, 20 with respect to the housing 14
As the power piston 22 also advances with respect to the input member 27 as the power piston 22 advances, the movable portion 41 of the valve member 45 approaches the air inflow control annular valve seat 37. Further, the advancement of the power piston 22 causes the reaction disk 54 to move between the rear surface of the center portion thereof and the input member 2.
7, i.e., into the inside of the guide member 53 so as to reduce a gap that is substantially ag-α between the first and second abutting portions 301 and 302. Contact parts 301, 30
The reaction disk 54 abuts on the front surface of the input member 2 to transmit the forward force of the power piston 22 and the forward force of the input member 27 to the output rod 55, and simultaneously applies a reaction force corresponding to the output from the output rod 55 to the input member 27. The input member 27 is provided so as to be retracted with respect to the power piston 22. This input member 27 is the reaction disk 5
In a state in which the power piston 22 is to be moved rearward with respect to the power piston 22 by receiving a reaction force, a gap of approximately e + g + α exists between the rear surface of the first contact portion 301 and the contact surface 51a. ing.

By receiving a reaction force from the reaction disk 54, the input member 27 and the valve seat member 40 engaged with the input member 27 are moved rearward relative to the power piston 22 by a distance of approximately f + α. When the input member 27 moves rearward, a gap of approximately e + g + α between the rear surface of the first contact portion 301 and the contact surface 51a is set as e + g ≦ f in the initial state. It becomes 0. That is, the rear surface of the first contact portion 301 comes into contact with the contact surface 51a.

Since the rear surface of the first contact portion 301 comes into contact with the contact surface 51a, the first contact portion 301 moves backward integrally with the main body portion 30a, and thus with the second contact portion 302, ie, , The rearward movement with respect to the power piston 22 is restricted. Since the rearward movement of the first contact portion 301 is restricted, the reaction disk 54 can no longer move the first contact portion 301 rearward, and the reaction force from the reaction disk 54 at the input member 27 is no longer available. The contact surface on which is applied is only the front surface of the second contact portion 302. The reaction disk 54 enters the center hole 301a of the first contact portion 301 and acts only on the front surface of the second contact portion 302, and moves the input member 27 except the first contact portion 301 to the rear side.

As the power piston 22 advances with respect to the input member 27, the movable portion 41 comes into contact with the air inflow control annular valve seat 37, and the valve mechanism 36 enters the output holding state. The position of the input member 27 in the front-rear direction with respect to the power piston 22 at this time is shifted rearward by the displacement amount f with respect to the same front-rear position in the normal braking operation, and the reaction disk 54 accommodates the yoke and reaction disk. The amount of entry into the member 51 is larger than the amount of entry during normal braking. That is, the forward force transmitted from the power piston 22 to the output rod 55 via the reaction disk 54 (the output rod 55
Is greater than that during normal braking, and the value Fo in FIG.
2. In other words, the first thrust of the power piston 22 generated by the brake operation at the input Fi1 is:
The output Fo1 is exerted via the output rod 55, but when the automatic operation mechanism 48 is operated, a second thrust is generated in the power piston 22 and the auxiliary output of [Fo2-Fol] is generated on the output rod 55. Is added, and Fo2, which is the sum of the main output Fo1 and the auxiliary output [Fo2-Fol], is output as the brake booster 10.

Transformation chamber 2 when output is at value Fo2 in FIG.
The pressure at 4,26 is lower than atmospheric pressure. Therefore, when the input applied to the input member 27 is increased by a value less than the value Fi2 in FIG. 3, the input member 27 is advanced with respect to the power piston 22, and the valve mechanism 36 is changed from the output holding operation state to the output increasing operation state. Switching is performed, and the pressure in the transformation chambers 24 and 26 increases, and the output increases. And the power piston 22 is the first
By moving forward with respect to the input member 27 other than the contact portion 301, the valve mechanism 36 switches from the output increasing operation state to the output holding operation state, and the increase in output stops.

When the input of the input member 27 is reduced, the input member 27 except for the first contact portion 301 is moved by the reaction force from the reaction disk 54 to the power piston 22.
, The valve mechanism 36 is switched to the output reducing operation state, the pressure in the variable pressure chambers 24 and 26 is reduced, and the output is reduced. Then, when the power piston 22 retreats with respect to the input member 27, the valve mechanism 36 is switched from the output decreasing operation state to the output holding operation state, and the decrease in output stops.

The output value Fo3 in FIG. 3 indicates the value when the pressure in the transformation chambers 24 and 26 has increased to the atmospheric pressure, and the input at this time is the value Fi2. The input is the value Fi1 and the value F
i2, the ratio of the output to the input, in other words, the amount of change in the input applied to the input member 27, and the main output and the auxiliary output from the output rod 55 corresponding to the amount of change in the input. The ratio of the total output to the change amount of the total output, that is, the inclination from the input Fi1 to Fi2 in the characteristic line at the time of the emergency braking operation shown in FIG. The ratio of the area of the front surface of the second contact portion 302 to the area of the front surface of the reaction disk 54 is the same. In the range where the input is larger than the value Fi2, the output changes by the change of the input.

When the driver releases the depression of the brake pedal while the solenoid coil 49 is energized, the input member 27 and the input member 27 are applied to the input member 27 in the same manner as when the depression of the brake pedal is released in the normal braking operation. The engaged valve member 40 is retracted with respect to the power piston 22 by the reaction force applied from the reaction disk 54 and the spring 59. As a result, the valve mechanism 36 is switched to the output reducing operation state, and the pressure
The pressure decreases at 4, 26 and the output decreases. As a result, the input member 27, the movable walls 17, 20, the power piston 22, and the output rod 55 are retracted with respect to the housing 14, and eventually return to the inactive state shown in FIG.

When the condition for de-energizing the solenoid coil 49 is satisfied, the electronic control unit sets the solenoid coil 49
Is de-energized. Thereby, the valve seat member 40 and the plunger 52 are retracted by the urging spring 72 and returned to the position shown in FIG. 4, and the operation of the automatic operation mechanism 48 is completed.

The other operation and effect are the same as those of the first embodiment, and the description is omitted.

(Embodiment 3) FIG. 5 is a sectional view showing the vicinity of a valve mechanism and an automatic operating mechanism of a tandem-type vehicle brake booster according to an embodiment of the present invention. The same members as those in the first embodiment are denoted by the same reference numerals. Except for the input member 27, the valve mechanism 36, and the automatic operation mechanism 48, the configuration is substantially the same as that of the first embodiment, and thus the description is omitted.

The input member 27 has a rear member 28, a rear end connected to a ball joint at the front end of the rear member 28, and a central member 29 directly slidably supported by the power piston 22. A front member 30 is screwed and fixed to the front end of the central member 29, and is connected to a brake pedal (not shown) at the rear end of the rear member 28.

The front member 30 has, at its front end, an annular first contact portion 301 and a cylindrical second contact portion 302 that can contact a reaction disk 54 described later. The main body 30a includes a first contact portion 301 and a second contact portion 302 and a flange portion 34. 2nd contact part 3
Reference numeral 02 is inserted into the center hole 301a of the first contact portion 301 so as to be slidable in the axial direction of the center hole 301a (the left-right direction in FIG. 5).

The main body 30a of the front member 30 has a first regulating portion having a diameter larger than the diameter of the second contact portion 302 which is disposed continuously behind the second contact portion 302. Is formed. The shoulder portion 303 has its front portion abutting against the rear surface of the first contact portion 301, so that the second contact portion 302 of the first contact portion 301, and thus the main body portion 3.
The backward limit position with respect to 0a is defined.

Input member 27 for power piston 22
A key member 32 for defining the forward limit position and the retreat limit position is provided. The central portion of the key member 32 is located between the flange portion 34 of the front member 30 and the front end of the central member 29. Input member 2 for power piston 22
The forward and backward limit positions of the input member 27 and the backward limit position of the input member 27 with respect to the housing 14 are the same as those of the first embodiment. Passages 60 and 61 are provided in the power piston 22.
Are formed.

The valve mechanism 36 is provided so as to be able to move forward and backward with respect to the input member 27 and the power piston 22, and has a valve seat member 40 having an air inflow control annular valve seat 37 facing rearward. An air outflow control annular valve seat 38 formed integrally with the power piston 22 and facing rearward; a movable portion 41 opposed to the air inflow control annular valve seat 37 and the air outflow control annular valve seat 38; Retainer 4
2 and a fixed portion 43 which is hermetically fixed to the power piston 22 by the
4 and a cylindrical valve member 45 urged forward by 4. On the outer periphery of the central member 29 of the input member 27, a seal member 7 for maintaining airtightness between the central member 29 and the valve seat member 40 is provided.
0 is attached.

An automatic operation mechanism 48 is provided inside the front part of the power piston 22. The automatic operation mechanism 48 includes a solenoid coil 49 installed so as to be able to move forward and backward with respect to the power piston 22, and yokes 50 and 71 made of a magnetic material installed so as to be able to move forward and backward with respect to the power piston 22. And a plunger 52 made of a magnetic material.

The solenoid coil 49 is electrically connected to an electronic control device outside the housing 14 by a lead wire. The rear end of the plunger 52 is connected to the front end of the valve seat member 40. When the solenoid coil 49 is energized, that is, when the automatic operation mechanism 48 is operated, an electromagnetic attraction force is generated between the yoke 71 and the plunger 52.

When the automatic operation mechanism 48 is not operated, the valve seat member 4
A spring for urging the valve seat member 40 rearward with respect to the input member 27 to position the valve seat member 40 with respect to the input member 27 so as to move the valve seat member 40 forward and backward integrally with the input member 27 at the retreat limit position with respect to the input member 27. 72 is provided between the central member 29 of the input member 27 and the valve seat member 40, and an opposing contact portion is formed by the inner peripheral rear end 52 a of the plunger 52 and the front surface of the flange portion 34 of the input member 27. Have been.

When the automatic operation mechanism 48 operates, the valve seat member 40
Is located at a forward position with respect to the input member 27, and the valve seat member 40 and the central member 29 are connected to the automatic operating mechanism 4 in this forward position so that the two can be integrally retracted.
8 which are in contact with each other when actuated
a.

Further, a stopper 73 fixed to the outer periphery of the front member 30 of the input member 27 so that the automatic operation mechanism 48 can move integrally with the input member 27 as the input member 27 advances and retreats. Inner circumference front end 71a of yoke 71
And a spring 74 for urging the yoke 71 forward with respect to the input member 27.
Between the flange portion 34 and the yoke 71.

The front end 52b of the plunger 52 and the yoke 71
And a rear end 71b of the inner peripheral portion constitute an opposing contact portion.

The reaction disk accommodating member 51 accommodates the reaction disk 54 in the front side thereof, and has the main body 30a, the first and second contact portions 301, 3
02 is slidably guided. In the initial state, the first contact portion 301 is
A contact surface 51a is disposed as a second restricting portion that is separated from the rear surface by a predetermined distance e. The contact surface 51a comes into contact with the first contact portion 301 when the input member 27 moves rearward when the automatic operation mechanism 48 to be described later is operated, so that the power piston of the first contact portion 301 is moved. 22 is restricted from moving backward.

The rear end 71b of the yoke 71 and the plunger 52
When the automatic operation mechanism 48 is not operated, that is, in the state shown in FIG. 5, the front end 52b is separated from the front end 52b by a predetermined amount f. The engaging portions 40a and 29a are separated by a predetermined distance f when the automatic operation mechanism 48 is not operated, that is, in the state shown in FIG.

In the initial state shown in FIG. 5, the air inflow control annular valve seat 37 is brought into contact with the movable portion 41 of the valve member 45, and the movable portion 41 is connected to the first air outflow control annular valve seat 3.
8 and a predetermined amount g of distance separation.

Each predetermined amount e in the initial state shown in FIG.
The relationship between f and g is set so that e + g ≦ f.

The urging force of the spring 74 is
And the sliding resistance of the automatic operation mechanism 48 with respect to the power piston 22 and the input member 27 is larger than that of the automatic operating mechanism 48, and the biasing force of the spring 72 is larger than the biasing force of the spring 44. Then, the distances f and h shown in FIG.
Is greater than the distance g, and the distance i is greater than the distance δ.
Further, the distance j shown in FIG. 5 is larger than the distance a in FIG.

The input-output characteristics of the embodiment of FIG. 5 are the same as those of FIG. 3, and the operation will be described with reference to FIGS. The state shown in FIG. 5 shows a non-operating state in which the normal braking operation and the emergency braking operation are not performed. The rod 55 is located at the retreat limit position with respect to the housing 14, and the valve mechanism 36 is configured such that the air inflow control annular valve seat 37 of the valve seat member 40 located at the retreat limit position with respect to the input member 27 41, in which the movable portion 41 is separated from the annular valve seat 38 for controlling the outflow of the air of the power piston 22, that is, in a state where the output is reduced.
The pressures of the pressure chambers 4 and 26 are equal to the pressures of the constant pressure chambers 23 and 24.

When the driver depresses the brake pedal to apply an input to the input member 27 for normal braking, the flange portion 34 of the input member 27 and the inner peripheral rear end portion 52a of the plunger 52 are engaged. , The input member 27, the plunger 52 and the valve seat member 40 are integrally advanced with respect to the power piston 22, and the movable portion 41 of the valve member 45 is moved to the air outlet control annular valve seat 3 of the power piston 22.
8, the valve mechanism 36 is switched to the output holding operation state. The yokes 71 and 50 and the solenoid 49 also advance integrally with the input member 27 by being urged by the spring 74 as the input member 27 advances. At this time, a gap remains between the first contact part 301 and the second contact part 302 and the reaction disk 54, and this gap is substantially equal to a-g. The rear surface of the first contact portion 301 and the contact surface 51a are separated from each other by a distance of substantially e + g. In addition, the reaction disk storage member 51 and the yoke 71
, A gap still remains, and this gap is substantially equal to jg.

Next, the input member 2 is switched from the output holding operation state.
7 further moves forward by the distance of α, the air inflow control annular valve seat 37 is separated from the movable portion 41, the valve mechanism 36 is switched to the output increasing operation state, and the air flows into the transformer chambers 24, 26. The pressure in the transformation chambers 24 and 26 rises,
20, the power piston 2, and the output rod 55 integrally start to advance with respect to the housing 14.

In this case, the power piston 22 is connected to the input member 2
7, the movable portion 41 of the valve member 45 approaches the air inflow control annular valve seat 37. In addition, the reaction disk 54 reduces a gap of approximately ag-α between the rear surface of the center portion and the front end surface of the input member 27, that is, the first and second contact portions 301 and 302. After entering the inside of the reaction disk housing member 51 and abutting against the front surfaces of the first and second contact portions 301 and 302, the reaction disk 54 applies the forward force of the power piston 22 and the forward force of the input member 27 to the output rod 55. Transmission and output rod 5
The reaction force corresponding to the output from 5 is applied to the input member 27 so that the input member 27 is retracted with respect to the power piston 22. In a state where the input member 27 is receiving a reaction force from the reaction disk 54 and is to be moved rearward with respect to the power piston 22, there is substantially no space between the rear surface of the first contact portion 301 and the contact surface 51 a. e + g
There is a gap of + α.

When the power piston 22 advances with respect to the input member 27, the movable part 4 of the valve member 45 is eventually formed.
1 again comes into contact with the annular valve seat 37 for controlling the inflow of air into the variable pressure chamber 2.
The flow of air into the air conditioners 4 and 26 is stopped (the valve mechanism 36 is switched to the output holding state). At this time, the input member 27 is moving backward by less than approximately e + g + α, in other words, approximately α, with respect to the power piston 22, so that the first contact portion 301 contacts the contact surface 51a. I will not touch you. That is, when the input member 27 moves backward, the first contact portion 301 and the second contact portion 302 move backward integrally. In the normal braking operation, the input applied from the brake pedal 31 to the input member 27 is the value Fi1 shown in FIG. 3, and the output applied from the output rod 27 to the master cylinder is the value Fo1 shown in FIG. It is. That is, the first propulsive force of the power piston 22 generated by the brake operation at the input Fi1 is output to the outside of the device as the main output Fo1 via the output rod 55.

Thereafter, as the input applied to the input member 27 is increased or decreased between the value Fi1 and the value Fi3 in FIG. 3, the valve mechanism 36 is switched between the output increasing operation state, the output holding operation state, and the output decreasing state. By switching the input value F
Output values Fo1 to Fo4 having magnitudes corresponding to i1 to Fi3
Is output from the output rod 55. If the input is Fi3
When it is increased above, the output increases by the amount of the input.

The input applied to the input member 27 is the value Fi1.
In the above case, the reaction force is applied from the reaction disk 54 to the first and second contact portions 30 as in the embodiment of FIGS.
1, 302, the input member 27 is provided.

When the input applied to the input member 27 is removed, the input member 27 is retracted with respect to the power piston 22 by the reaction force applied to the input member 27 from the reaction disk 54 and the spring 59, and the valve mechanism is actuated. 36 is switched to the output reduction operation state, the atmosphere in the transformation chambers 24 and 26 is exhausted, and the pressure in the transformation chambers 24 and 26 is reduced. Is integrated into the housing 1
4 starts retreating, and finally returns to the position of FIG. Since the stopper 73 provided on the input member 27 is engaged with the yoke 71, the yokes 50 and 71 and the solenoid 49 are also moved with the input member 2 with the retreat of the input member 27.
7 will be retracted together.

The ratio of the output to the input when the input is Fi1 to Fi3, in other words, the change in the input applied to the input member 27 and the output rod 5 corresponding to the change in the input.
5 is the ratio of the change of the main output to the output, that is, the input Fi1 to F1 in the characteristic line at the time of the normal braking operation shown in FIG.
The inclination at i3 is caused by the first and second contact portions 301, 3 of the input member 27 to which the reaction force from the reaction disk 54 acts.
02 of the output rod 55 with respect to the area of the front surface
And the ratio of the contact area between the rear surface and the front surface of the reaction disk 54.

Next, when the driver depresses the brake pedal rapidly with the input Fi1 (FIG. 3) for the emergency braking action, the input member 27, the valve seat member 40, and the automatic operating mechanism 48 are connected to the power piston 22. The valve mechanism 36 as described in the description of the normal braking action.
Is switched from the output decreasing operation state to the output holding operation state.

When the input member 27 advances, the front end face of the input member 27, that is, the first and second contact portions 301 and 302 are provided.
A gap remains between the front surface of the reaction disk 54 and the rear surface of the reaction disk 54, and this gap is substantially equal to a-g.
The rear surface of the first contact portion 301 and the contact surface 51a are substantially e +
g.

Then, as the input member 27 is further advanced by the distance α, the air inflow control annular valve seat 37 is moved to the valve member 45.
The variable pressure chamber 26 is separated from the movable portion 41, and communicates with the atmosphere, and the valve mechanism 36 switches to the output increasing operation state. In parallel with the operation of the brake pedal 31, the electronic control unit energizes the solenoid coil 49, so that the automatic operation mechanism 48 is operated.

When the solenoid coil 49 is energized, an electromagnetic attractive force is generated between the plunger 52 and the yoke 71, and the plunger 52 is advanced with respect to the power piston 22 to advance the valve seat member 40 by the distance f. , Valve seat member 4
The air release control annular valve seat 37 is further separated from the movable portion 41 of the valve member 45 from the separation amount α to α + f. As the plunger 52 and the valve seat member 40 advance,
The front end 52b of the plunger 52 is connected to the rear end 7 of the yoke 71.
1b, the engaging portion 40a of the valve seat member 40 contacts the engaging portion 29a of the central member 29, thereby restricting the forward movement of the valve seat member 40 with respect to the input member 27. By such an operation, the gap between the air inflow control annular valve seat 37 and the movable portion 41 of the valve member 45 is increased to the maximum amount.
Therefore, by the operation of the brake pedal and the operation of the automatic operation mechanism 48, the air quickly flows into the transformation chambers 24, 26,
The pressure in the transformation chambers 24, 26 rises quickly, and the movable walls 17,
20, the power piston 22 and the output rod 55 advance rapidly with respect to the housing 14.

The movable walls 17, 20 with respect to the housing 14
As the power piston 22 also advances with respect to the input member 27 as the power piston 22 advances, the movable portion 41 of the valve member 45 approaches the air inflow control annular valve seat 37. In addition, as the power piston 22 advances, the reaction disk 54 is moved to the rear surface of the center portion thereof and the front end surface of the input member 27, that is, the first,
The guide member 53 enters the inside of the guide member 53 so as to reduce a gap of approximately ag-α between the second contact portions 301 and 302, and contacts the front surfaces of the first and second contact portions 301 and 302. In contact with the reaction disk 54, the advancing force of the power piston 22 and the advancing force of the input member 27 are transmitted to the output rod 55, and the reaction force corresponding to the output from the output rod 55 is applied to the input member 27 by the input member 27. The piston 22 is provided so as to retreat. This input member 2
In a state where the actuator 7 is moved rearward with respect to the power piston 22 by receiving the reaction force from the reaction disk 54, the distance between the rear surface of the first contact portion 301 and the contact surface 51a is approximately e + g + α. There are gaps.

The input member 27, the valve seat member 40 engaged with the input member 27, and the automatic operating mechanism 48 when the reaction force is applied from the reaction disk 54 move the power piston 22 backward by a distance of approximately f + α. Moved a minute,
When the input member 27 moves rearward, a gap of approximately e + g + α between the rear surface of the first contact portion 301 and the contact surface 51a is set as e + g ≦ f in the initial state. Becomes 0. That is, the rear surface of the first contact portion 301 comes into contact with the contact surface 51a.

Since the rear surface of the first contact portion 301 comes into contact with the contact surface 51a, the first contact portion 301 moves backward integrally with the main body portion 30a and thus with the second contact portion 302, ie, , The rearward movement with respect to the power piston 22 is restricted. Since the rearward movement of the first contact portion 301 is restricted, the reaction disk 54 can no longer move the first contact portion 301 rearward, and the reaction force from the reaction disk 54 at the input member 27 is no longer available. The contact surface on which is applied is only the front surface of the second contact portion 302. The reaction disc 54 enters the center hole 301a of the first contact portion 301 and acts only on the front surface of the second contact portion 302, and the input member 27 excluding the first contact portion 301;
The valve seat member 40 and the automatic operation mechanism 48 engaged with the input member 27 are moved rearward.

When the power piston 22 advances with respect to the input member 27, the movable portion 41 comes into contact with the air inflow control annular valve seat 37, and the valve mechanism 36 enters the output holding state. The position of the input member 27 in the front-rear direction with respect to the power piston 22 at this time has shifted rearward by a distance of the displacement amount f with respect to the same position in the front-rear direction at the same time in the normal braking operation. The amount of entry into the member 51 is larger than the amount of entry during normal braking. In other words, the forward force transmitted from the power piston 22 to the output rod 55 via the reaction disk 54 (the output applied from the output rod 55 to the master cylinder) is larger than that during normal braking. Medium value Fo2
It is. In other words, the first thrust of the power piston 22 generated by the brake operation at the input Fi1 is exerted as the output Fo1 via the output rod 55,
When the automatic operation mechanism 48 is operated, a second propulsive force is generated in the power piston 22, and an auxiliary output of [Fo 2 -Fo 1] is added to the output rod 55. Fo2, which is the sum of the output Fo1 and the auxiliary output [Fo2-Fol], is output.

Transformation chamber 2 when output is value Fo2 in FIG.
The pressure at 4,26 is lower than atmospheric pressure. Therefore, when the input applied to the input member 27 is increased by a value less than the value Fi2 in FIG. 3, the input member 27 is advanced with respect to the power piston 22, and the valve mechanism 36 is changed from the output holding operation state to the output increasing operation state. Switching is performed, and the pressure in the transformation chambers 24 and 26 increases, and the output increases. And the power piston 22 is the first
By moving forward with respect to the input member 27 other than the contact portion 301, the valve mechanism 36 switches from the output increasing operation state to the output holding operation state, and the increase in output stops.

When the input of the input member 27 is reduced, the input member 27 except for the first contact portion 301 is moved by the reaction force from the reaction disk 54 to the power piston 22.
, The valve mechanism 36 is switched to the output reduction operation state, the pressure in the rear chambers 24 and 26 is reduced, and the output is reduced. Then, when the power piston 22 retreats with respect to the input member 27, the valve mechanism 36 is switched from the output decreasing operation state to the output holding operation state, and the decrease in output stops.

The output value Fo3 in FIG. 3 indicates the value when the pressure in the transformation chambers 24 and 26 has increased to the atmospheric pressure, and the input at this time is the value Fi2. The input is the value Fi1 and the value F
i2, the ratio of the output to the input, in other words, the amount of change in the input applied to the input member 27, and the main output and the auxiliary output from the output rod 55 corresponding to the amount of change in the input. The ratio between the total output and the amount of change in the total output, that is, the inclination from the input Fi1 to Fi2 in the characteristic line at the time of the emergency braking operation shown in FIG. The rear end portion 56 of the output rod 55 with respect to the contact area of the contact portion 302 with the front surface.
And the ratio of the area of the rear surface to the area of the front surface of the reaction disk 54. In the range where the input is larger than the value Fi2, the output changes by the change of the input.

When the driver releases the brake pedal while the solenoid coil 49 is energized, the input member 27 and the input member 27 are applied to the input member 27 in the same manner as when the brake pedal is released during the normal braking operation. The engaged valve member 40 and the automatic operating mechanism 4
8 is retracted with respect to the power piston 22 by the reaction force applied from the reaction disk 54 and the spring 59. As a result, the valve mechanism 36 is switched to the output reducing operation state, the pressure in the variable pressure chambers 24, 26 is reduced, and the output is reduced. Thereby, the input member 27, the movable walls 17, 2
0, the power piston 22 and the output rod 55 are retracted with respect to the housing 14, and eventually return to the inactive state shown in FIG.

When the condition for deenergizing the solenoid coil 49 is satisfied, the electronic control unit sets the solenoid coil 49
Is de-energized. As a result, the valve seat member 40 and the plunger 52 are retracted by the urging spring 72 and returned to the position shown in FIG. 5, and the operation of the automatic operation mechanism 48 ends.

The other functions and effects are the same as those of the first embodiment, and the description is omitted.

As described above, the present invention has been described based on the above embodiments. However, the present invention is not limited to the above embodiments, but includes various embodiments according to the principle of the present invention.

[0186]

As described above, according to the first aspect of the present invention, for example, when the input / output ratio at the time of emergency braking operation is made larger than the input / output ratio at the time of normal braking operation, There is no need to increase the size of the automatic operation mechanism. Alternatively, the input member does not increase in size.

Therefore, it is possible to provide a negative pressure type booster that can be reduced in size.

According to the second aspect of the present invention, in addition to the effects of the first aspect of the present invention, a better mode of the changing mechanism is shown. According to the third aspect of the invention, in addition to the effect of the second aspect of the invention, a better mode of the input member and the change mechanism is shown.

According to the fourth aspect of the invention, in addition to the effect of the third aspect, a better form of the first contact portion and the second contact portion and a better form of the change mechanism are shown. .

According to the fifth aspect of the present invention, in addition to the effects of any one of the first to fourth aspects, a better mode of the valve mechanism and the automatic operating mechanism is shown.

According to the sixth aspect of the invention, in addition to the effects of any one of the first to fourth aspects, a better mode of the valve mechanism and the automatic operation mechanism is shown.

According to the seventh aspect of the present invention, in addition to the effect of the sixth aspect, a better form of the valve seat member and the input member is shown.

According to the eighth aspect of the invention, in addition to the effects described in any one of the first to fourth aspects, a better mode of the valve mechanism and the automatic operation mechanism is shown.

According to the ninth aspect of the invention, in addition to the effect of the eighth aspect, a better mode of the valve seat member and the input member is shown.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a vacuum booster 10 according to a first embodiment.

FIG. 2 is a partially enlarged sectional view of FIG.

FIG. 3 is a performance diagram of the vacuum booster 10 according to the embodiment.

FIG. 4 is a partially enlarged sectional view of a negative pressure type booster of a second embodiment.

FIG. 5 is a partially enlarged sectional view of a negative pressure type booster of a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Negative pressure type brake booster 14 Housing 17, 20 Movable wall 23, 25 Constant pressure chamber 24, 26 Transformation chamber 22 Power piston 27 Input member 29a Engagement part 301 First contact part 302 Second contact part 303 Shoulder part 36 Valve mechanism 37 Annular valve seat for air inflow control 38 Annular valve seat for air outflow control 40 Valve seat member 40a Engagement part 41 Movable part 43 Fixed part 44 Spring 45 Valve member 48 Automatic operation mechanism 49 Solenoid coil 50 Yoke 51 Reaction disk accommodation member 51a , 531 Contact surface 54 Reaction disk 55 Output rod

Claims (9)

[Claims] A housing that forms at least one pressure chamber therein; a front chamber that is installed in the housing so as to be able to move forward and backward with respect to the housing, and communicates the pressure chamber with a negative pressure source. A movable wall divided into a rear chamber selectively connected to the negative pressure source and the atmosphere; a power piston coupled to the movable wall; and a forward / backward movement of the power piston inside the power piston with respect to the power piston. An input member installed in the power piston, the output member being disposed in the power piston, and communicating the rear chamber with the front chamber and shutting off from the atmosphere according to the movement of the input member. Valve mechanism for switching between a state, an output holding operation state in which the rear chamber is isolated from the front chamber and the atmosphere, and a power increasing operation state in which the rear chamber is isolated from the front chamber and communicated with the atmosphere An output member that outputs the first propulsive force of the power piston along with the movement of the movable wall by the brake operation to the outside of the device as a main output, and the valve mechanism independently of the movement of the input member. An automatic operation mechanism for generating a second propulsive force on the power piston to add an auxiliary output to the output member in an output increasing action state, and disposed between the input member and the output member; When the first thrust is generated in the piston, the first
Applying a reaction force corresponding to the propulsive force of the power piston to the input member to move the input member rearward to shift the valve mechanism from the output increasing operation state to the output holding operation state, and the power piston When the second propulsion is generated, a reaction force corresponding to the second propulsion is applied to the input member to move the input member rearward, thereby setting the valve mechanism to the output increasing operation state. To the output holding operation state, and abuts the input member on the rear side and the output member on the front side thereof, and the contact between the area of the input member on which the reaction force acts and the output member. With a reaction force member that determines a ratio of the sum of the main output and the auxiliary output output by the input member and the output member at the ratio of the contact area and the output member, with the operation of the automatic operation mechanism, The input unit A change mechanism for changing a ratio of an area of the material on which the reaction force acts and a contact area between the reaction force member and the output member. 2. The vacuum booster according to claim 1, wherein the change mechanism changes an area of the input member on which the reaction force acts. 3. The input member includes a first contact portion that contacts the reaction member at a first area and a second contact portion that contacts the reaction member at a second area. In the state, the first contact portion and the second contact portion receive the reaction force from the reaction member, and the changing mechanism causes the input member to move the reaction member along with the operation of the automatic operation mechanism. The second
The negative pressure booster according to claim 2, wherein the reaction force is received by the second contact portion by contacting the contact portion with the contact portion. 4. The first contact portion has an annular shape, and the second contact portion has an annular shape.
The contact portion has a cylindrical shape that is inserted into the center hole of the first contact portion so as to be slidable in the axial direction of the center hole, and the input member is the second contact portion of the first contact portion. A first restricting portion for restricting the rearward movement of the input member when the input member is moved rearward by the reaction member accompanying the operation of the automatic operating mechanism. The negative pressure booster according to claim 3, further comprising a second restricting portion that restricts the rearward movement of the power piston with respect to the power piston. 5. An air flow control annular valve seat integrated with the input member and facing rearward, and the atmosphere integrated with the power piston and facing rearward. An annular valve seat for outflow control, a movable portion opposed to the annular valve seat for atmospheric inflow control and the annular valve seat for atmospheric outflow control, and a fixed portion hermetically fixed to the power piston; and The movable portion includes a valve member that is biased forward by a biasing member, and the automatic operation mechanism is selectively connected to an electric power source, and receives the supply of electricity to cause the valve mechanism to move the valve mechanism. A solenoid coil and a yoke fixed to the power piston, a plunger moved rearward by an electromagnetic attraction generated by energizing the solenoid coil, and a front plunger. The air outlet control annular valve seat is disposed on the inner diameter side so as to be able to move forward and backward with respect to the power piston, and is moved rearward by the movement of the plunger to move the movable portion to the atmosphere inflow control annular valve seat and the The negative pressure booster according to any one of claims 1 to 4, further comprising a valve seat member that is separated from the air outlet control annular valve seat. 6. A valve seat member having an annular valve seat for air inflow control facing rearward and capable of moving forward and backward integrally with the input member as the input member moves. An air outflow control annular valve seat integrated with the power piston and facing rearward; a movable portion facing the air inflow control annular valve seat and the air outflow control annular valve seat; A fixed portion that is hermetically fixed to a power piston, and a movable member that includes a valve member that is urged forward by an urging member. Selectively connected,
The valve mechanism is set to the output increasing operation state by receiving supply of electricity, and the solenoid coil and the yoke fixed to the power piston and the electromagnetic attraction generated by energizing the solenoid coil move forward. The plunger moves the valve seat member forward with respect to the input member by being moved, and detaches the movable portion from the air inflow control annular valve seat and engages with the air outflow control annular valve seat. The negative pressure doubler according to any one of claims 1 to 4, wherein the valve seat member is always moved rearward integrally with the input member by the rearward movement of the input member due to the reaction force. Power device. 7. The valve seat member and the input member abut upon each other when the automatic actuating mechanism is actuated to move the valve seat member forward by a predetermined amount with respect to the input member. 7. The vacuum booster according to claim 6, further comprising an engagement portion that regulates forward movement of the valve seat member with respect to the input member. 8. A valve seat member having an annular valve seat for air inflow control facing rearward and normally being able to move forward and backward integrally with the input member as the input member moves. An air outflow control annular valve seat integrated with the power piston and facing rearward; a movable portion opposed to the air inflow control annular valve seat and the air outflow control annular valve seat; A fixed portion that is hermetically fixed to the power piston, and a cylindrical valve member whose movable portion is urged forward by an urging member. Selectively connected to
The valve mechanism is set to the output increasing operation state by receiving supply of electricity, and the input mechanism is disposed so as to be able to move forward and backward with respect to the power piston, and the input member is moved along with the input member. The solenoid coil and the yoke that are integrally moved, and the valve seat member are moved forward by being moved forward by an electromagnetic attraction force generated by energizing the solenoid coil, and the movable section is controlled by the air inflow control. A plunger which is disengaged from the annular valve seat for use and engages with the annular valve seat for air outflow control, wherein the valve member is always integrated with the input member by the rearward movement of the input member by the reaction force. The vacuum booster according to any one of claims 1 to 4, which is moved rearward. 9. The valve seat member and the input member abut upon each other when the automatic actuating mechanism is actuated to move the valve seat member forward by a predetermined amount with respect to the input member, 9. The vacuum booster according to claim 8, further comprising a contact portion that restricts forward movement of the valve seat member with respect to the input member.